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InterviewSolution
This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
| 701. |
Polyphosphates are used for softening agents because theyA. form soluble complexes with anionic speciesB. precipitate anionic speciesC. form soluble complexes with cationic speciesD. precipitate cationic species. |
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Answer» Correct Answer - C Polyphosphates (sodium hexametaphosphate, sodium tripolyphosphate or STPP) form soluble complexes with `Ca^(2+),Mg^(2+)` present in hard water. |
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| 702. |
Amongest `H_(2)O,H_(2)S,H_(2)Se` and `H_(2)Te` the one with highest boiling point is :A. `H_(2)O`, because of hydrogen bondingB. `H_(2)` Te, because of higher molecular weightC. `H_(2)S`, because of hydrogen bondingD. `H_(2)Se`, because of lower molecular weight |
| Answer» Correct Answer - A | |
| 703. |
The correct order in which the O-O bond length increases in the following isA. `O_(3)ltH_(2)O_(2)ltO_(2)`B. `O_(2)ltO_(3)ltH_(2)O_(2)`C. `O_(2)ltH_(2)O_(2)ltO_(3)`D. `H_(2)O_(2)ltO_(2)ltO_(3)`. |
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Answer» Correct Answer - B Bond length increases as the bond order (within brackets) decreases i.e. `O_(2)(2)ltO_(3)(1.5)ltH_(2)O_(2)(1)` |
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| 704. |
Which one of the following ionic species has the greatest proton affinity to form stable compound ?A. `I^(-)`B. `HS^(-)`C. `NH_(2)^(-)`D. `F^(-)`. |
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Answer» Correct Answer - C Stronger the base, stronger is the proton affinity `ClNH_(2)^(-)`. |
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| 705. |
Which of the following gives `H_(2)` with Na metal?A. `CH_(4)`B. `C_(2)H_(6)`C. `C_(2)H_(4)`D. `C_(2)H_(2)` |
| Answer» (d) `C_(2)H_(2)+2Na to Na_(2)C_(2)+H_(2)` | |
| 706. |
Which of the following has the highest proton affinity ?A. Stibin `(SbH_(3))`B. Arsinie `(AsH_(3))`C. Phosphie `(PH_(3))`D. `Ammonia (NH_(3))` |
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Answer» Correct Answer - D High electron density on small `N` atom repel lone pair, making it more available for protonation. From `P` to `Bi` size of atom increases and so lone pair becomes less available for protonation. |
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| 707. |
Proton is likely to have high:A. Hydration energyB. Electron affinityC. Atomic sizeD. Atomic mass |
| Answer» (a) Proton is likely to have high hydration energy due to its very small size. | |
| 708. |
The reagent commonly used todetermine the hardness of water titrametrically is:A. Oxalic acidB. disodium salt of EDTAC. sodium citrateD. sodium thiosulphate |
| Answer» (b) Disodium salt of ethylene diamine tetra acetic acid (EDTA) is used to estimate `Ca^(2+) and Mg^(2+)` ions responsible for the hardness of water volumentrically of titrametrically | |
| 709. |
Which of the following is not true ?A. Ordinary water is electrolysed more rapidly than `D_(2)O`.B. Reaction between `H_(2)` and `Cl_(2)` is much faster than `D_(2)` and `Cl_(2)`.C. `D_(2)O` freezes at lower temperature than `H_(2)O`.D. Bond dissociation energy for `D_(2)` is greater than `H_(2)`. |
| Answer» Correct Answer - C | |
| 710. |
Select the incorrect statement from the following :A. `H^(+)` can exist as `H_(9)O_(4)^(+)` in water.B. `H_(2)` is thermally stable.C. Ionisation of `CH_(3)COOH` is slower than that of `CH_(3)COOD`.D. Kinetic isotopic effect is observed when there is retardation in the rate if `H_(2)O` is replaced by `D_(2)O`. |
| Answer» Correct Answer - C | |
| 711. |
In the Following reaction using isotope `""^(18)O` in `H_(2)O_(2)`. `2MnO_(4)^(-) + 3H_(2)O_(2)^(18) to 2MnO_(2) + 3O_(2) + 2H_(2)O + 2OH^(-)` Isotopic oxygen goes :A. both in `O_(2)`B. both in `MnO_(2)`C. both in `OH^(-)`D. One in `O_(2)` and one in `MnO_(2)` |
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Answer» Correct Answer - A `H_(2)""^(18)O_(2) (aq) + 2OH^(-) (aq) to 2H_(2)O (l) + ""^(18)O_(2) (g) + 2e^(-)` So, all the `""^(18)O` label appers in `""_(18)O_(2)` |
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| 712. |
In the following reaction using isotopic `.^(18)O` in `H_(2)O_(2), 2MnO_(4)^(-)+3H_(2)O_(2)^(18)rarr 2MnO_(2)+3O_(2)+2H_(2)O+2OH^(-)` isotopic oxygen goes,A. with `O_(2)`B. with `MnO_(2)`C. with `OH^(-)`D. one with `O_(2)` and one with `MnO_(2)` |
| Answer» Correct Answer - A | |
| 713. |
Assertion `: H_(2)` molecule is more stable than `He-H ` molecule . Reason `:` The antibonding electron in `He-H` molecule decreases the bond order thereby the stability.A. If both assertion and reason are true and the reason is the correct explanation of the assertion.B. If both assertion and reason are true but reason is not the correct explanation of the assertion.C. If assertion is true but reason is false.D. If assertion is false but reason is true. |
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Answer» Correct Answer - a Bond order for `H_(2)=1` Bond order for `He-H=(1)/(2)`. |
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| 714. |
How do you expect the metallic hydrides to be useful for hydrogen storage? |
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Answer» In metallic hydrides, hydrogen is adsorbed as H-atoms. Due to the adsorption of H atoms the metal lattice expands and become unstable. Thus, when metallic hydride is heated, it decomposes to form hydrogen and finely divided metal. The hydrogen evolved can be used as fuel. |
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| 715. |
The metal which gives `H_(2)` on treatment with acid as well as NaOH isA. FeB. CuC. ZnD. Hg |
| Answer» Correct Answer - C | |
| 716. |
Which of the following reaction produces hydrogen ?A. `H_(2)SO_(4)O_(8)+H_(2)O`B. `BaO+HCl`C. `Mg+H_(2)O`D. `Na_(2)O_(2)+2HCl` |
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Answer» Correct Answer - c `Mg+2H_(2)O rarr Mg(OH)_(2) +H_(2)uarr` |
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| 717. |
In which of the following compounds does hydrogen have an oxidation state of `-1 `?A. `PH_(3)`B. `NH_(3)`C. `HCl`D. `CaH_(2)` |
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Answer» Correct Answer - d In `CaH_(2),H` has oxidation state `(-1)[+2+2x=0,x=-1]` |
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| 718. |
The oxidation states exhibites by hydrogen in its various compounds are `:`A. `-1` onlyB. Zero onlyC. `+1,-1` and zero.D. `+1` only. |
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Answer» Correct Answer - c Oxidation number for hydrogen in hydrogen molecule and hydrogen atom is zero. Oxidation number of hydrogen in all compoun containing hydrogen is `+1` except hydrides. Oxidation no. of hydrogen ini hydrides is `-1`. |
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| 719. |
Out of the following metals which will give `H_(2)` on reaction with `NaOH:` `I: Zn,` ,`II:Mg`, `III: Al,`,`IV:Be`A. I, II, III, IVB. I, III, IVC. II, IVD. I, III |
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Answer» Correct Answer - B Amphoteric metal produces `H_(2)` gas with `NaOH, Zn, Al, Be`. |
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| 720. |
The oxidation states exhibited by hydrogen in its various compounds areA. `-1` onlyB. zero onlyC. `+1,-1` and zeroD. `+1 ` only |
| Answer» Correct Answer - C | |
| 721. |
Weakest reducing agent:A. Atomic hydrogenB. Nascent hydrogenC. Molecular hydrogenD. Occluded hydrogen |
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Answer» Correct Answer - C Molecular hydrogen-most stable form of Hydrogen. |
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| 722. |
Nuclear isomerism is exhibited by-A. Molecules H onlyB. All diatomic moleculeC. All diatomic molecule having even Z valueD. All diatomic molecule having odd Z value. |
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Answer» Correct Answer - D All diatomic molecule having odd z value. |
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| 723. |
In which property listed below hydrogen does not resemble alkali metals ?A. Tendency to form cationB. Nature of oxideC. Combination with halogensD. Reducing character |
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Answer» Correct Answer - B Oxide of hydrogen `(H_(2)O)` is neutral while oxides of alkali metals are strong basic. |
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| 724. |
Which of the following compound is used as Antichlor in bleaching to remove excess chlorine ?a) Waterb) Hydrogen peroxidec) Hard waterd) Hydrochloric acid |
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Answer» b) Hydrogen peroxide |
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| 725. |
Statement-1: `H_(2)O_(2)` can be used as an antichlor in bleaching Statement-2:It oxidises `HCl"to"Cl_(2)` |
| Answer» (c ) `H_(2)O_(2)` reduces `Cl_(2)` to HCl and thus removes chlorine. | |
| 726. |
Correlate the items listed in Column I with those listed in Column II. Find out as many correlations as you can.Column IColumn II(i) Synthesis gas(a) Na2[Na4(PO3)6](ii) Dihydroge(b) Oxidising agent(iii) Heavy water(c) Softening of water(iv) Calgon(d) Reducing agent(v) Hydrogen peroxide(e) Stoichiometric compounds of s-block elements(vi) Salt like hydrides(f) Prolonged electrolysis of water(g) Zn + NaOH(h) Zn + dil. H2SO4(i) Synthesis of methanol(j) Mixture of CO and H2 |
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Answer» (i) → (i), (j) (ii) → (d), (e), (g), (h), (i) (iii) → (f) (iv) → (a), (c) (v) → (b), (d) (vi) → (e) |
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| 727. |
How will you account for 104.5° bond angle in water? |
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Answer» In H2O molecule the oxygen is sp3 −hybridizedand thus, tetrahedral configuration comes into existence. Two positions are occupied by H atoms by forming sigma bonds with two hybrid orbitals and two positions are occupied by lone pairs. The expected bond angle should be109.5∘, but the actual angle is 104.5∘. The lone pair-lone pair repulsions are greater than bond pair-bond pair repulsions. As a result, bond angle in water is reduced from 109.5o to 104.5o. |
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| 728. |
What is the oxidation number of oxygen in hydrogen peroxide? |
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Answer» Let, oxidation number of oxygen in H2O2 = x |
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| 729. |
The velocity of neutrons in nuclear is slowed down byA. Heavy water `(D_(2)O)`B. Ordinary water `(H_(2)O)`C. Zinc rodD. Fused caustic soda. |
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Answer» Correct Answer - A Heavy water i.e. , `D_(2)O` slows down the speed of neutrons in nuclear reactors. |
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| 730. |
Why does hard water not from lather with soap ? |
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Answer» Hard water conatins `Ca^(2+) and Mg^(2+)` ions which of the soap to froms corresponding calcium and magnesium salts that are insoluble and get precipitated. Therefore, soap is simpluy wasterd without producing any lather. `underset("Soap")(2RCOONA)+underset("(Hard water")(Ca^(2+))tounderset("(ppt)")((RCOO)_(2))Ca+2Na^(+)` `underset("Soap")(2RCOONa)+underset("(Hard water)")(Mg^(2))tounderset("(ppt)")((RCOO)_(2))Mg+2Na^(+)` |
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| 731. |
Why does hard water not form lather with soap ? |
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Answer» Hard water contains bicarbonates , chlorides and sulphates of `Ca^(2+)` and `Mg^(2+)` . These combine with soap molecules to form precipiatates of calcium and magnesium salts of soaps. `underset("(Soap)")underset("Sod. Stearate")(2C_(17)H_(35)COONa)+Ca^(+) to underset("(Curdy white ppt.)")underset("Cal. stearate")((C_(17)H_(35)COO)_(2)Ca)+ 2Na^(+)` `underset("(Soap)")underset("Sod. Stearate")(2C_(17)H_(35)COONa)+Mg^(2+) to underset("(Curdy white ppt.)")underset("Mag. stearate")((C_(17)H_(35)COO)_(2)Mg)+2Na^(+)` As a result , soap is wasted and hence hard water does not produce lather with soap. |
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| 732. |
Hydrogen generally form covalent compounds. Give reason |
| Answer» The compounds of hydrogen are generally. This is mainly due to high ionisation enthalpy of the element. `(Delta_(i)H_(1)=1312KJmol^(-1))`. As a result it cannot accept an electron easily to form `H^(-)` ion (noble gas configuratoin). Similarly, it is not a positive to lse electron to from `H^(+)` ion beceause the size of ion (proton) in extremely small and it cannot exist indepedently. Therefore. the compounds of hydrogen are generally covalent in nature in which hydrogen atom shares its electrons with atoms of other elements (generally non metals) | |
| 733. |
Why is the ionisation enthalpy of hydrogen higher than that of sodium ? |
| Answer» The ionisation enthalpy of hydrogen is higher than that of sodium due to its very small size. As a result, the hold of the nucleus on the only electron present in the K-shell is more as compared to sodium atom where the valence electron to the removed in present in M-Shell. | |
| 734. |
Phosphoric acid is preferred over sulphuric acid in preparing hydrogen peroxide from peroxides. Why? |
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Answer» In the preparation of H2O2 from barium peroxide and sulphuric acid, the use of sulphuric acid has a disadvantage as it catalyses the decomposition of H2O2 formed. In place of H2O2, weak acids like ortho phosphoric acid, carbonic acid are preferred. All heavy metal impurities present in BaO2 are removed as insoluble phosphates and decomposition of H2O2 is prevented. |
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| 735. |
Hydrogen molecules areA. Monoatomic and form `X_(2)^(2-)` type ionsB. Diatomic and form `X_(2)^(-)` type ionsC. Diatomic and form `X^(-)` as well as `X^(-1)` type ionD. Monoatomic and form X type ion. |
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Answer» Correct Answer - C Zinc decomposes water on heating. |
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| 736. |
Assertion (A) Hydrogen peroxide forms only one series of salts called peroxides. Reason (R ) Hydrogen peroxide molecule has only one replaceable hydrogen atom.A. Both A and R are true and R is the correct explanation of AB. Both A and R are true but R is not a correct explanation of AC. A is true but R is falesD. Both A and R are fales. |
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Answer» Correct Answer - D Both assertion (A) and reason (R ) are not true. Correct Assertion. Hydrogen peroxide forms two series of salts called hydroperoxides and peroxides. Correct Reason. Hydrogen peroxide molecule has two replaceable hydrogen atoms. |
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| 737. |
Which compound/s is/are saline hydride?A. `CaH_(2)`B. `HCl`C. `ScH_(2)`D. `SrH_(2)` |
| Answer» Correct Answer - A::D | |
| 738. |
Heavy water isA. `H_(2)O` with dissolved `Mg(HCO_(3))_(2)`B. `D_(2)O`C. `D_(2)O` with heavy metal impuritiesD. `H_(2)O` with `CaCO_(3)` |
| Answer» Correct Answer - B | |
| 739. |
Which among the following is interstitial hydride?A. `ScH_(2)`B. `LaH_(2)`C. `TiH_(17)`D. All of these |
| Answer» Correct Answer - D | |
| 740. |
In which of the compounds does hydrogen have an oxidation state of -1 ?A. `CH_(4)`B. `NH_(3)`C. `HCl`D. `CaH_(2)`. |
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Answer» Correct Answer - D `overset(+2)(Ca)overset(x)(H_(2))i.e., 2+2x=0rArrx=-1` |
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| 741. |
Consider the following reactions I. `AlH_(3)+H^(-)toAlH_(4)^(-)` II. `H_(2)O+H^(-)toH_(2)+OH^(-)` Select the correct statement based on these reactions.A. `H^(-)` is a lewis acid in I and lewis base in IIB. `H^(-)` is a lewis base in I and brosted base in IIC. `H^(-)` is a lewis acid in I and brosted acid in IID. `H^(-)` is a lewis base in I and II |
| Answer» Correct Answer - B | |
| 742. |
Consider the following reactions: I : `AIH_(3)+ H^(-) to AlH_(4)^(-)` II : `H_(2)O + H^(-) to H_(2) + OH^(-)` Select the correct statement from the following :A. `H^(-)` is a Lewis acid in I and Lewis base in IIB. `H^(-)` is a Lewis acid in I and Bronsted base in IIC. `H^(-)` is a Lewis acid in I and Bronsted base in IID. `H^(-)` is a Lewis base in I and II |
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Answer» Correct Answer - B `H^(-)` ion is a Lewis base in I and Bronsted base in II. |
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| 743. |
Which of the following compounds is used for water softening ?A. `Ca_(3)(PO_(4))_(2)`B. `Na_(3)PO_(4)`C. `Na_(6)P_(6)O_(18)`D. `Na_(2)HPO_(4)` |
| Answer» (c ) `Na_(6)P_(6)O_(18)` (Calogen) is used for water softining | |
| 744. |
Elements of which of the following group(s) of periodic table do not form hydrides.A. Groups 7,8,9B. Group 13C. Groups 15,16, 17D. Group 14 |
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Answer» Correct Answer - A Elements of 7,8,9 do not hydrides and hence is called hydride gap. |
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| 745. |
Elements of which of the following group(s) of periodic table do not form hydrides?A. Groups 7,8,9B. Group 13C. Groups 15, 16, 17D. Group 14 |
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Answer» Correct Answer - A The metals of group 7, 8 and 9 do not form hydrides. |
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| 746. |
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 |
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Answer» (a) Group 7, 8, 9 elements do not form hydrides. |
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| 747. |
Hydrogen acts as an oxidising agent in the reaction with `:`A. BromineB. CalciumC. NitrogenD. Sulphur. |
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Answer» Correct Answer - B `Ca+overset((0))(H_(2))toCaoverset((-1))H_(2)` In this reaction `H_(2)` is an oxidising agent because its oxidation number decreases from zero to -1. |
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| 748. |
Why does water show high boling points as compared to hydrogen sulphide? Given reason for answer. |
| Answer» Boiling point tmperature of water (373K) is more than intemolecular hydrogen bonding is present in the molecule of `H_(2)O`. As a result, the attractive forces in the molecules are more than `H_(2)S` molecules of `H_(2)O`. As a result, the arractive forces in the molecules are more than in `H_(2)S` molecules in which these faorces are only dipolar in nature. | |
| 749. |
Elements of which of the following group(s) of periodic table do not form hydrides?A. Groups 7,8,9B. Group 13C. Groups 15,16,17D. Groups 14 |
| Answer» (a) Elements belonging to groups 7,8 and 9 (d-block elements) normally donot form hydirdes. | |
| 750. |
Why is water molecule polar ? |
| Answer» Water is polar to the difference in the electronegative of oxygen and hydrogen atoms because of its angular shape `("bond angle"=104.5^(@)`. | |