Solution: Fuel cell: Energy components are gadgets for creating power from fuel within the sight of an electrolyte. Dihydrogen can be utilized as a fuel in these cells. It is liked over different...
What do you understand by the term :Water-gas shift reaction
Solution: Water-gas shift response: It is a response of carbon monoxide of syngas blend with steam within the sight of an impetus as: $\mathrm{CO}_{(g)}+\mathrm{H}_{2} \mathrm{O}_{(g)} \rightarrow...
What do you understand by the term :‘syngas’
Solution: 'syngas': Syngas is a combination of carbon monoxide and dihydrogen. Since the combination of the two gases is utilized for the blend of methanol, it is called syngas amalgamation gas, or...
What do you understand by the term :Hydrogenation
Solution: Hydrogenation: The method involved with adding dihydrogen to one more reactant is known as hydrogenation. It is utilized to decrease a compound within the sight of appropriate impetus. For...
What do you understand by the terms: Hydrogen economy ?
Solution: Hydrogen economy: Dihydrogen delivers more energy than petroleum and is more eco-accommodating. Subsequently, it tends to be utilized in energy units to create electric force. Hydrogen...
Do you expect different products in solution when aluminium (III) chloride and potassium chloride treated separately with (i) alkaline water (ii) acidified water, and (iii) normal water. Write equations wherever necessary.
Solution: Potassium chloride $(\mathrm{KCl})$ is the salt of a solid corrosive $(\mathrm{HCl})$ and solid base (KOH). Consequently, it is nonpartisan in nature and doesn't go through hydrolysis in...
What do you expect the nature of hydrides is, if formed by elements of atomic numbers 15,19, 23 and 44 with dihydrogen? Compare their behaviour with water.
Solution: The components of nuclear numbers 15 is phosphorus, 19 potassium, 23 is vanadium and 44 is ruthenium Hydride of Phosphorus Hydride of phosphorus $\left(\mathrm{PH}_{3}\right.$ ) is...
How can saline hydrides remove traces of water from organic compounds?
Solution: Normally, saline hydrides are ionic. Saline hydrides responds with water which brings about the arrangement of metal hydroxide alongside hydrogen gas freedom. It is addressed as, $A...
What is the difference between the terms ‘hydrolysis’ and ‘hydration’?
Solution: Hydration: The expansion of at least 1 atoms to a particle or particle which brings about arrangement of hydrated mixtures is known as hydration. For example $\mathrm{CuSO}_{4}+5...
Write chemical reactions to justify that hydrogen peroxide can function as an oxidising as well as reducing agent.
Solution: Hydrogen peroxide goes about as an oxidizing specialist just as diminishing specialist in both basic medium and acidic medium. The response which are associated with oxidizing activities...
Write chemical reactions to show the amphoteric nature of water
Solution: The amphoteric idea of water can be depicted based on the accompanying responses: 1) Reaction with $\mathrm{H}_{2} \mathrm{~S}$ The response happens as: $\mathrm{H}_{2}...
Discuss the principle and method of softening of hard water by synthetic ionexchange resins.
Solution: The method involved with treating extremely durable hardness of water utilizing engineered saps commonly based or trade of anions and cations present in water by $\mathrm{OH}^{-}$and...
Complete the following chemical reactions. (i) $\mathrm{Pb} S_{(g)}+\mathrm{H}_{2} \mathrm{O}_{2(a q)} \rightarrow$ (ii) $\mathrm{MnO}_{4 a q}^{-}+\mathrm{H}_{2} \mathrm{O}_{2(a q)} \rightarrow$ (iii) $\mathrm{CaO}_{(g)}+\mathrm{H}_{2} \mathrm{O}_{(g)} \rightarrow$ (iv) $A l C l_{3(g)}+H_{2} O_{(l)} \rightarrow$ (v) $\mathrm{Ca}_{3} \mathrm{~N}_{2(g)}+\mathrm{H}_{2} \mathrm{O}_{(l)} \rightarrow$ Classify the above into (a) Hydrolysis, (b) Redox and (c) Hydration reactions.
Solution: (I) $\mathrm{PbS}_{(g)}+4 \mathrm{H}_{2} \mathrm{O}_{2(a q)} \rightarrow \mathrm{PbSO}_{4(s)}+4 \mathrm{H}_{2} \mathrm{O}_{(l)}$ $\mathrm{H}_{2} \mathrm{O}_{2}$ is going about as an...
Consider the reaction of water with $\mathrm{F}_{2}$ and suggest, in terms of oxidation and reduction, which species are oxidized/reduced.
Solution: The response among water and fluorine can be addressed as: $2 F_{2(g)}+2 H_{2} O_{(l)} \rightarrow 4 H_{(a q)}^{+}+4 F_{(a q)}^{-}+O_{2(g)}$ This is an illustration of redox response $2...
What do you understand by the term ‘auto-protolysis’ of water? What is its significance?
Solution: Auto-protolysis (self-ionization) of water is a compound response wherein 2 water atoms respond to deliver a hydroxide particle $\left(\mathrm{OH}^{-}\right)$and a hydronium particle...
Saline hydrides are known to react with water violently producing fire. Can $\mathrm{CO}_{2}$, a well known fire extinguisher, be used in this case? Explain.
Solution: Saline hydrides [i.e.,LiH, NaH etc.] respond with water to shape hydrogen gas Furthermore, a base. The synthetic condition to address this response is $M H_{(g)}+H_{2} O_{(a q)}...
What characteristics do you expect from an electron-deficient hydride with respect to its structure and chemical reactions?
Solution: To shape an ordinary bond, an electron-lacking hydride doesn't have adequate electrons in which 2 electrons are shared by 2 particles. e.g., $B_{2} H_{6}$ $\mathrm{Al}_{2} \mathrm{H}_{6}$...
Complete the following reactions: (i) $H_{2(g)}+M_{m} O_{0(g)} \rightarrow$ (ii) $C O_{(g)}+H_{2(g)} \rightarrow$ (iii) $C_{3} H_{8(g)}+3 H_{2} O_{(g)} \rightarrow$ (iv) $Z n_{(g)}+N a O H_{(a q)} \rightarrow$
Solution: (i) $H_{2(g)}+M_{m} O_{0(g)} \rightarrow m M_{(s)}+H_{2} O_{(l)}$ (ii) $\mathrm{CO}_{(g)}+\mathrm{H}_{2(g)} \rightarrow \mathrm{CH}_{3} \mathrm{OH}_{(l)}$ (iii) $\mathrm{C}_{3}...
Describe the bulk preparation of dihydrogen by electrolytic method. What is the role of an electrolyte in this process?
Solution: The readiness of di hydrogen is by the electrolysis of fermented or soluble water utilizing platinum anodes Generally, $15-20 \%$ of a corrosive $\left(\mathrm{H}_{2}...
Write the names of isotopes of hydrogen. What is the mass ratio of these isotopes?
Solution: 3-isotopes are: (i) tritium ${ }_{1}^{3} H$ or $\mathrm{T}$ (ii) protium ${ }_{1}^{3} H$ (iii) deuterium ${ }_{1}^{2} H$ or $\mathrm{D}$ Mass Ratio: Tritium : Protium : deuterium $=1: 2:...
How does H2 O2 act as a dying specialist?
Solution: Hydrogen peroxide goes about as a solid oxidizing specialist both in fundamental and acidic media. When added to a material, it breaks the substance obligations of the chromophores...
Knowing the properties of H2O and D2O, do you imagine that D2O can be utilized for drinking purposes?
Solution: D2O is referred to as weighty water which goes about as an arbitrator (dials back the pace of response). Because of this property, it can't be utilized for drinking reason since it dials...
Portray the helpfulness of water in biosphere and organic frameworks.
Solution: Water is extremely important for all types of life which establish 65% of human body and 95% of plants.it assumes an indispensable part in the biosphere because of its → Thermal...
Is demineralised or refined water valuable for drinking purposes? If not, how might it be made valuable?
Solution: Water is extremely fundamental for our life. It comprises of many broke down supplements that are needed for ourselves and furthermore for plants and creatures. Demineralised water is...
What is implied by ‘demineralised’ water and how might it be acquired ?
Solution: This water is liberated from every one of the solvent mineral salts and it doesn't contain any cation or anion. It is acquired progressively by going the water through anion trade and...
What causes the impermanent and super durable hardness of water?
Solution: Because of the presence of dissolvable salts of magnesium and calcium as chlorides in water, hardness stays super durable in water. Because of the presence of dissolvable salts of calcium...
Portray the construction of the normal type of ice.
Solution: For the most part, ice is the translucent type of water. It visibles in a hexagonal structure in case it is solidified at climatic strain. At the point when the temperature is...
Analyze the designs of H2O and H2 O2.
Solution: The water atom will be shown with a bond point of 104 .5o has a bowed structure in vaporous stage. The O-H bond length is 95.7 pm. Structure : Hydrogen peroxide has a non-planar design...
Organize the accompanying NaH, MgH2 and H2O arranged by expanding diminishing property.
Solution: Ionic hydrides are solid diminishing specialists. NaH can undoubtedly give its electrons. Henceforth, it is most diminishing in nature. Both, MgH2 and H2O are covalent hydrides. H2O is...
Organize the accompanying H–H, D–D and F–F arranged by expanding bond separation enthalpy.
Solution: The bond pair in D–D bond is more emphatically drawn in by the core than the bond pair in H–H bond. This is a direct result of the greater atomic mass of D2. The more grounded the...
Organize the accompanying LiH, NaH and CsH arranged by expanding ionic person.
Solution: The ionic person of a bond is reliant upon the electro negativities of the molecules in question. The higher the distinction between the electro negativities of molecules, the more modest...
Organize the accompanying CaH2, BeH2 and TiH2 arranged by expanding electrical conductance.
Solution: The electrical conductance of an atom chiefly relies upon its covalent or ionic nature. CaH2 is an ionic hydride, which conducts power in the liquid state. Titanium hydride, TiH2 is...
Among NH3, H2O and HF, which would you hope to have most noteworthy greatness of hydrogen holding and why?
Solution: The degree of hydrogen holding predominantly relies upon (I) Electronegativity (ii) Number of hydrogen iotas accessible for holding. Among oxygen, fluorine and nitrogen, the expanding...
How does the nuclear hydrogen or oxy-hydrogen light capacity for cutting and welding purposes ? Clarify.
Solution: The nuclear hydrogen light is otherwise called oxy-hydrogen light. These molecules are delivered through dihydrogen separation with the assistance of an electric circular segment which...
How would you anticipate that the metallic hydrides should be valuable for hydrogen stockpiling? Clarify
Solution: Metallic hydrides are hydrogen inadequate. They don't keep the law of consistent structure. It has been set up that in the hydrides of Pd, Ac, Ni, and Ce, hydrogen possesses the...
What do you comprehend by the expression “non-stoichiometric hydrides”? Do you anticipate that this type of the hydrides should be framed by soluble base metals? Legitimize your reply.
Solution: Non-Stoichiometric hydrides are hydrogen-insufficient mixtures which is framed by the response of dihydrogen with d-square and f-block components. These hydrides don't observe the law of...
Do you expect the carbon hydrides of the sort (Cn H2n+2 ) to go about as ‘Lewis’ base or corrosive? Legitimize.
Solution: For carbon hydrides which have a place with type (Cn H2n+2), the accompanying hydrides are feasible for \[\begin{array}{*{35}{l}} n\text{ }=\text{ }1\Rightarrow CH4 \\ ~ \\...
What do you comprehend by (I) electron rich – mixtures of hydrogen, (ii) electron-exact, and (iii) electron-lacking? Give avocation appropriate models.
Solution: Sub-atomic hydride is grouped based on the presence of the bonds and absolute number of electrons in their Lewis structures as: Electron-inadequate hydrides Electron-exact hydrides...
Talk about the results of high enthalpy of H–H bond as far as synthetic reactivity of dihydrogen
Solution: The ionization enthalpy of H–H bond is higher (1312 kJ mol–1 ) which shows that hydrogen has a low propensity to frame H+ particles. Its ionization enthalpy esteem is equivalent to that of...
For what reason does hydrogen happen in a diatomic structure instead of in a monoatomic structure under ordinary conditions?
Solution: The ionization enthalpy of hydrogen molecule is higher. In this manner, it is more enthusiastically to eliminate its electron. This outcomes its propensity to exist in the low monoatomic...
Legitimize the situation of hydrogen in the intermittent table based on its electronic design.
Solution: The first component in the occasional table is hydrogen. Hydrogen shows double conduct since it has just 1 electron on its one 'S' shell.(i.e.,) hydrogen takes after the two incandescent...
Which of the following statements is correct? (i) Metallic hydrides are deficient of hydrogen. (ii) Metallic hydrides conduct heat and electricity. (iii) Ionic hydrides do not conduct electricity in solid-state. (iv) Ionic hydrides are very good conductors of electricity in solid-state.
Solution: Option (i), (ii) and (iii) are the answers. Metallic hydrides are hydrides that are not stoichiometric in nature. They are excellent conductors of heat and electricity. Ionic hydrides...
Which of the following statements is correct? (i) Hydrides of group 13 act as Lewis acids. (ii) Hydrides of group 14 are electron deficient hydrides. (iii) Hydrides of group 14 act as Lewis acids. (iv) Hydrides of group 15 act as Lewis bases.
Solution: Option (i) and (iv) are the answers. Group 13 elements create electron-deficient compounds and are thus Lewis acids. Electron-rich hydrides have lone pairs of extra electrons. Compounds of...
Which of the following statements is correct? (i) Elements of group 15 form electron deficient hydrides. (ii) All elements of group 14 form electron precise hydrides. (iii) Electron precise hydrides have tetrahedral geometries. (iv) Electron rich hydrides can act as Lewis acids.
Solution: Option (ii) and (iii) are the answers. Inorganic electron-specific hydrides are those hydrides in which the exact quantity of electrons required to form a typical covalent bond is present....
The hardness of water may be temporary or permanent. Permanent hardness is due to the presence of (i) Chlorides of Ca and Mg in water (ii) Sulphates of Ca and Mg in water (iii) Hydrogen carbonates of Ca and Mg in water (iv) Carbonates of alkali metals in water
Solution: Option (i) and (ii) are the answers. Permanent hardness is caused by the presence of soluble magnesium and calcium salts in the form of chorides and sulphates in the water, which causes...
Some of the properties of water are described below. Which of them is/are not correct? (i) Water is known to be a universal solvent. (ii) Hydrogen bonding is present to a large extent in liquid water. (iii) There is no hydrogen bonding in the frozen state of water. (iv) Frozen water is heavier than liquid water.
Solution: Option (iii) and (iv) are the answers. In ice, there is a great deal of hydrogen bonding. Because of the empty spaces found in tetrahedrons generated by hydrogen bonding, ice is...
Which of the following statement(s) is/are correct in the case of heavy water? (i) Heavy water is used as a moderator in a nuclear reactor. (ii) Heavy water is more effective as a solvent than ordinary water. (iii) Heavy water is more associated than ordinary water. (iv) Heavy water has a lower boiling point than ordinary water.
Solution: Option (i) and (iii) are the answers. Heavy water is a moderator in nuclear reactors. It has a greater boiling point than regular water. It is thus more associated than plain water....
Dihydrogen can be prepared on a commercial scale by different methods. In its preparation by the action of steam on hydrocarbons, a mixture of CO and H2 gas is formed. It is known as ____________. (i) Water-gas (ii) Syngas (iii) Producer gas (d) Industrial gas
Solution: Option (i) and (ii) are the answers. It is used to produce hydrogen, carbon monoxide, and other products from hydrocarbons like natural gas. This is done in a reformer, which uses...
Which of the following statements are not true for hydrogen? (i) It exists as a diatomic molecule. (ii) It has one electron in the outermost shell. (iii) It can lose an electron to form a cation which can freely exist (iv) It forms a large number of ionic compounds by losing an electron
Solution: Option (iii) and (iv) are the answers. Because hydrogen has only one electron in its outermost shell, it can form diatomic molecules by covalent bonding. Its high ionisation enthalpy...
Only one element of ________ forms hydride. (i) group 6 (ii) group 7 (iii) group 8 (iv) group 9
Solution: Option (i) is the answer. Chromium (Cr), the single element in group 6, is capable of forming hydride. Because of their poor affinity for hydrogen, the other elements do not combine to...
Elements of which of the following group(s) of periodic table do not form hydrides. (i) Groups 7, 8, 9 (ii) Group 13 (iii) Groups 15, 16, 17 (iv) Group 14
Solution: Option (i) is the answer. The elements in groups 7, 8, and 9 have a low affinity for hydrogen, as a result of which they have little potential to combine with hydrogen to create...
Which of the following compounds is used for water softening? (i) Ca3 (PO4) (ii) Na3PO4 (iii) Na6P6O18 (iv) Na2HPO4
Solution: Option (iii) is the answer. Water softening is done with sodium hexametaphosphate (Calgon). Calgon interacts with calcium/magnesium salts in hard water to create inactive complex anions...
Which of the following ions will cause hardness in the water sample? (i) Ca2+ (ii) Na+ (iii) Cl– (iv) K+
Solution: Option (i) is the answer. Ca++ ions in the form of Ca(HCO3)2 or CaCl2 or CaSO4 causing hardness in water, or more specifically, soluble calcium salts, is possible.
Which of the following reactions is an example of use of water gas in the synthesis of other compounds? (i) CH4 (g) + H2O (g) → (1270KNi) CO (g) + H2 (g) (ii) CO (g) + H2O (g) → (Catalyst673K) CO2 (g) + H2 (g) (iii) CnH2n+2 + nH2O (g) → (1270KNi) nCO + (2n+1) H2 (iv) CO (g) + 2H2 (g) Cobalt → (Catalyst) CH3OH (l)
Solution: Option (iv) is the answer. The mixture of carbon monoxide and hydrogen is referred to as water gas. The term "synthesis gas" or "syngas" refers to the mixture of carbon monoxide and...
Hydrogen peroxide is obtained by the electrolysis of ______. (i) water (ii) sulphuric acid (iii) hydrochloric acid (iv) fused sodium peroxide
Solution: Option (ii) is the answer. The simplest peroxide (oxygen-oxygen single bond) is hydrogen peroxide. It is an oxidizing agent utilized in many synthetic processes. In the industrial...
When sodium peroxide is treated with dilute sulphuric acid, we get ______. (i) sodium sulphate and water (ii) sodium sulphate and oxygen (iii) sodium sulphate, hydrogen and oxygen (iv) sodium sulphate and hydrogen peroxide
Solution: Option (iv) is the answer. In the reaction of sodium peroxide with dilute sulphuric acid, we obtain the byproduct sodium sulphate and hydrogen peroxide as a result.
Which of the following reactions increases production of dihydrogen from synthesis gas?(i) CH4 (g) + H2O (g) →(1270K Ni)CO (g) + 3H2 (g) (ii) C (s) + H2O (g) → (1270K) CO (g) + H2 (g) (iii) CO (g) + H2O (g)→ (Catalyst 673K) CO2 (g) + H2 (g) (iv) C2H6 + 2H2O → (1270K Ni) 2CO + 5H2
Solution: Option (iii) is the answer. The synthesis of dihydrogen can be boosted by mixing syngas carbon monoxide with steam and using iron chromate as a catalyst....
Why does the water show a high boiling point as compared to hydrogen sulphide? Give reasons for your answer.
Answer: The presence of electronegative elements like oxygen, fluorine, and nitrogen causes particularly stable intermolecular hydrogen bonding (bonding with other molecules of the same or other...
Why is water molecule polar?
Answer: A polar molecule is one that has a charge distribution that is slightly positive on one side and slightly negative on the other. It is possible to increase polarity by increasing the...
With the help of suitable examples, explain the property of H2O2 that is responsible for its bleaching action?
Answer: H2O2, also known as hydrogen peroxide, is a powerful oxidizing agent that can be used in both acidic and basic conditions. Because of the release of nascent oxygen, it has the effect of...
An acidic solution of hydrogen peroxide behaves as an oxidising as well as the reducing agent. Illustrate it with the help of a chemical equation.
Answer: Hydrogen peroxide (H2O2) is an oxygen hydride with the chemical formula H2O2. It has the ability to serve as an oxidizing as well as a reducing agent in both acidic and basic mediums,...
Write the Lewis structure of hydrogen peroxide.
Answer: Lewis structures are diagrams that represent the bonding between atoms in a molecule, as well as any lone pairs of electrons that may occur.
What is the importance of heavy water?
Answer: Heavy water is defined as water that contains a high concentration of heavy hydrogen (D2O). It is utilised as a moderator in nuclear reactors and exchange processes, and it is also employed...
The basic principle of a hydrogen economy is transportation and storage of energy in the form of liquid or gaseous hydrogen. Which property of hydrogen may be useful for this purpose? Support your answer with the chemical equation if required.
Answer: It is easier to transport because it is a liquid and consumes less volume than other forms of transportation. Consequently, the most fundamental attribute of hydrogen that is advantageous...
Why is the Ionisation enthalpy of hydrogen higher than that of sodium?
Answer: A valence electron from the H atom is harder to remove than from the Na atom because of the higher nuclear attraction, and hence more energy would be required. As a result, the ionization...
Hydrogen generally forms covalent compounds. Give reason.
Answer: Because hydrogen has just one electron in its outermost shell, it can either lose or gain an electron in order to achieve the noble gas configuration. Hydrogen has a high ionization...
Give reasons why hydrogen resembles alkali metals?
Answer: In its electronic form, hydrogen shares features with alkalis and halogens. Like alkali metals (ns1), hydrogen (1s1) has only one electron in its valence shell. So if they lose one electron,...
Rohan heard that instructions were given to the laboratory attendant to store a particular chemical i.e., keep it in the darkroom, add some urea in it, and keep it away from dust. This chemical acts as an oxidising as well as a reducing agent in both acidic and alkaline media. This chemical is important for use in the pollution control treatment of domestic and industrial effluents (i) Write the name of this compound. (ii) Explain why such precautions are taken for storing this chemical.
Answer: The compound hydrogen peroxide, which functions as both an oxidising and reducing agent in both acidic and alkaline conditions, is referred to as hydrogen peroxide. After coming into touch...
When the first element of the periodic table is treated with dioxygen, it gives a compound whose solid-state floats on its liquid state. This compound can act as an acid as well as a base. What products will be formed when this compound undergoes authorisation?
Answer: The first element, hydrogen, interacts with dioxygen to make water. Water is amphoteric, meaning it is both acid and basic. Water's solid state is ice. Due to its decreased density, it...
Explain why HCl is a gas and HF is a liquid.
Answer: In order to break the H-F bond, a large amount of energy must be expended in order to build a strong and stable hydrogen bond. As a result, the boiling point of HF is higher than that of...
(i) Draw the gas phase and solid phase structure of H2O2. (ii) H2O2 is a better oxidising agent than water. Explain.
Answer: i) The diagram shows the gas phase and solid phase structure of H2O2. ii) When the oxygen atom on H2O2 is reduced to -1, it is considered to be in an intermediate state of oxidation. Meaning...
Calculate the strength of 5 volume H2O2 solution.
Answer: $H_2O_2$ has a molar mass of 34gm and is a gas. According to this reaction, 2 moles of peroxide are involved, resulting in a total mass of 68g. We already know that 1mole of any gas occupies...
Write one chemical reaction for the preparation of $D_2O_2$
Answer: When $D_2SO_4$ interacts with $BaO_2, D_2O_2$ is generated, which is then followed by the formation of barium sulphate ($BaSO_4$). In the presence of $D_2SO_4 + BaO_2 → D_2O_2 +...
How is heavy water prepared? Compare its physical properties with those of ordinary water.
Answer: Heavy water, which is composed primarily of deuterium oxide (D2O), is produced primarily by the electrolysis of regular water. 1. Ordinary water has a molecular mass of 18.015 while heavy...
Molecular hydrides are classified as electron-deficient, electron precise and electron-rich compounds. Explain each type with two examples.
Answer: Molecular hydrides are classed as electron-deficient, electron-rich, or precise. B2H6 is an oxyhydroxide. They lack an octet. Generally, group 13 elements like B, Al, etc. create them. This...
Discuss briefly de-mineralisation of water by ion exchange resin.
Answer: Water is demineralized by passing it through anion and cation exchange resin. It has many of SO3H and COOH groups. A cation exchanger removes cations like Na+ and Mg+ from the water. OH-,...
What do you understand by the term ‘auto protolysis of water’? What is its significance?
Answer: Water that has undergone auto protolysis has undergone self ionisation. It is a chemical property of water that is important to understand. In this case, two identical molecules react to...
Give reasons: (i) Lakes freeze from top towards bottom. (ii) Ice floats on water.
Answer: i) The density of ice is lower than the density of water. Whenever the temperature dips below 4°C, coldwater begins to expand and become less dense than it should be in order to maintain its...
Complete the following equations. a) $P bS ( s )+ H _{2} O _{2}( aq ) \rightarrow$ b) $CO ( g )+2 H _{2}( g ) \underset{\text { Catalyst }}{\text { Cobalt }}$
Answer: (i) $PbS (s) + H_2O_2 (aq) → PbSO_4 + 4H_2O$ This is a redox reaction. PbS (oxidation state -2) is oxidized to PbSO4 (oxidation state +6) and H2O2 by hydrogen peroxide (oxidation state of O...
If the same mass of liquid water and a piece of ice is taken, then why is the density of ice less than that of liquid water?
Answer: When water freezes, it expands, resulting in a volume of ice that is more than the volume of the water for the same quantity of water. We can state that ice has a lower density than water...
Name the classes of hydrides to which $H_2O$, $B_2H_6$ and NaH belong.
Answer: A hydride is a hydrogen anion. It occurs when hydrogen forms a combination with a less electronegativity element. When hydrogen reacts with other elements, it generates hydrides. Ionic...
What are metallic/interstitial hydrides? How do they differ from molecular hydrides?
Answer: Heat conductivity and electrical conductivity of metal hydrides are quite high, while the conductivity and electrical conductivity of molecular hydrides are extremely low. Metallic hydrides...
How can production of hydrogen from water gas be increased by using water gas shift reaction?
Answer: It is necessary to apply the water shift gas process in the generation of synthesis gas (a mixture of hydrogen and carbon monoxide or carbon dioxide). CO is transformed to CO2 in this...
Hydrogen peroxide is _________. (i) an oxidising agent (ii) a reducing agent (iii) both an oxidising and a reducing agent (iv) neither oxidising nor reducing agent
Solution: Option (iii) is the answer. It is also known as dioxide or peroxide. It has a mild odor and is colorless in solution. With a stabilizer, it is non-flammable and somewhat acidic. An...
Which of the following equations depict the oxidising nature of $H 202$ ? (i) $2 MnO _{4}{ }^{-}+6 H ^{+}+5 H _{2} O _{2} \rightarrow 2 Mn ^{2+}+8 H _{2} O +50_{2}$ (ii) $2 Fe +2 H + H _{2} O _{2} \rightarrow 2 Fe ^{2+}+2 H _{2} O + O _{2}$ (iii) $2 I ^{-}+2 H ^{+}+ H _{2} O _{2} \rightarrow I _{2}+2 H _{2} O$ (iv) $KIO _{4}+ H _{2} O _{2} \rightarrow KIO _{3}+ H _{2} O + O _{2}$
Solution: Option (iii) is the answer. The oxidising characteristic of $H _2 O _2$ indicates that it oxidises other substances while simultaneously reducing itself. In such reactions, $O _2$ does not...
The oxide that gives H2O2 on treatment with dilute H2SO4 is — (i) PbO2 (ii) BaO2 .8H2O + O2 (iii) MnO2 (iv) TiO2
Solution: Option (ii) is the answer. The oxide that gives $H _{2} O _{2}$ on treatment with dilute $H _{2} SO _{4}$ is $BaO _{2} \cdot 8 H _{2} O$....
Consider the reactions (A) H2O2 + 2HI → I2 + 2H2O (B) HOCl + H2O2 → H3O++ Cl–+ O2 Which of the following statements is correct about H2O2 with reference to these reactions? Hydrogen peroxide is ________. (i) an oxidising agent in both (A) and (B) (ii) an oxidising agent in (A) and reducing agent in (B) (iii) a reducing agent in (A) and oxidising agent in (B) (iv) a reducing agent in both (A) and (B)
Solution: Option (ii) is the answer. (A) $H_2O_2 + 2HI → I_2 + 2H_2O$ Iodine undergoes oxidation, transitioning from the -1 oxidation state to the 0 oxidation state. As a result, H2O2 works as an...
Radioactive elements emit α, β and γ rays and are characterised by their halflives. The radioactive isotope of hydrogen is (i) Protium (ii) Deuterium (iii) Tritium (iv) Hydronium
Solution: Option (iii) is the answer. The concentration of tritium is approximately one atom per $10^18$ atoms of protium in the sample. Only tritium is radioactive and emits low-energy beta...
Which of the following hydrides is electron-precise hydride? (i) B2H6 (ii) NH3 (iii) H2O (iv) CH4
Solution: Option (iv) is the answer. The hydrides indicate an anion form of hydrogen atoms. ...
Metal hydrides are ionic, covalent or molecular in nature. Among LiH, NaH, KH, RbH, CsH, the correct order of increasing ionic character is (i) LiH > NaH > CsH > KH>RbH (ii) LiH < NaH < KH < RbH CsH > NaH > KH > LiH (iv) NaH > CsH > RbH > LiH > KH
Solution: Option (ii) is the answer. As we advance down the group, the ionic nature rises. As ionisation enthalpy drops from top to bottom in a group, metal tends to lose electron. So ionic...
Why does H+ ion always get associated with other atoms or molecules? (i) Ionisation enthalpy of hydrogen resembles that of alkali metals. (ii) Its reactivity is similar to halogens. (iii) It resembles both alkali metals and halogens. (iv) Loss of an electron from hydrogen atom results in a nucleus of very small size as compared to other atoms or ions. Due to the small size, it cannot exist free.
Solution: Option (iv) is the answer. Hydrogen has one electron in its s orbital and like alkali metals, it can lose one electron from its outer shell. So hydrogen is like alkalis. Onions reacting...
Hydrogen resembles halogens in many respects for which several factors are responsible. Of the following factors which one is most important in this respect? (i) Its tendency to lose an electron to form a cation. (ii) Its tendency to gain a single electron in its valence shell to attain stable electronic configuration. (iii) Its low negative electron gain enthalpy value. (iv) Its small size.
Solution: Option (ii) is the answer. Hydrogen, like halogens, prefers to gain an electron to achieve a stable noble gas structure. Hydrogen's electrical configuration is 1s. The electrical...