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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.
| 101. |
Which one is the higheset melting halide ?A. KCIB. KBrC. KFD. KI |
| Answer» Correct Answer - C | |
| 102. |
Assertion (A): `Li^(o+)` (aq) has large ionic redius than `Na^(o+)` (aQ). Reason (R ): `Li^(o+)` (aq) is relatively more hydrated as compared to `Na^(o+)` aq.A. If both (A) and (R ) are correct and (R ) is the correct explanation of (A).B. If both (A) and (R ) are correct, but (R ) is not the correct explanation of (A).C. If (A) is correct, but (R ) is incorrect.D. If (A) is incorrect, but (R ) is correct. |
| Answer» Correct Answer - A | |
| 103. |
The densities of Li, Na and K followed the orderA. `Li gt Na lt K`B. `Li lt Na lt K`C. `Li lt K lt Na`D. `Li gt Na gt K` |
| Answer» Correct Answer - C | |
| 104. |
The size of `Na^(o+)` ion is same as that ofA. Ne atomB. Na atomC. K atomD. None of these |
| Answer» Correct Answer - D | |
| 105. |
In the electrolysis of NaCI solution, for the manufacture of NaOH, the ion discharged at cathode is `H^(o+)`. |
| Answer» Correct Answer - T | |
| 106. |
How many `Na^(o+)` ions sorround each `CI^(Θ)` ion in `NaCI` crystal lattice ?A. 4B. 6C. 8D. 12 |
| Answer» Correct Answer - B | |
| 107. |
`K^(o+)` ion is isolectronic withA. `Na^(o+)`B. `Ne`C. `Ar`D. `Cs^(o+)` |
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Answer» Correct Answer - C `K^(o)` ion and Ar have the same electronic configuration due to the same number of electrons. |
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| 108. |
Which of the following oxides is not expected to react with sodium hydroxide ?A. `CaO`B. `SiO_(2)`C. `BeO`D. `B_(2)O_(3)` |
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Answer» Correct Answer - A `CaO` being basic oxide will not react with base, NaOH. |
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| 109. |
Pick out statement (s) which is/are not true about diagonal relationship of Li and Mg: A. Polarising powers of `Li^(o+)` and `Mg^(2+)` ions are almost the same. B. Like Li, Mg decomposes water very fast. C. LiCI and `MgCI_(2)` are deliquesent. D. Like Li, Mg readily reacts with liquid bromine at ordinary temperaure.A. A and DB. B and CC. Only BD. B and D |
| Answer» Correct Answer - D | |
| 110. |
A white solid is either `Na_(2)O` or `Na_(2)O_(2)`. A piece of red litmus paper turns white when it is dipped into a freshly made aqueous solution of the white solid. a. Identify the substance and explain the balanced equation. b. Explain what would happen to the red litmus if the white solid were the other compound. |
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Answer» a. `Na_(2)O_(2)+2H_(2)O rarr 2NaOH+H_(2)O_(2)` `H_(2)O_(2)rarr H_(2)O+[O]` `H_(2)O_(2)` turns the colour of red litmus paper to white edue to its bleaching action by oxidation. Therefore, the given substance is `Na_(2)O_(2)`, b. `Na_(2)O+H_(2)O rarr 2NaOH` If the given substance was `Na_(2)O_92)` it would form only `NaOH`, which turns the colour of red litmus paper to blue. |
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| 111. |
The reaction of sodium is highly exothermic with water. The rate of reaction is lowered by making an ______________ . |
| Answer» Correct Answer - Amalgan | |
| 112. |
Li reacts directly with nitrogen to from lithium nitride. |
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Answer» Correct Answer - T `6Li+N_(2)rarr 2Li_(3)N` |
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| 113. |
Assertion (A): `Na_(2)CO_(3)` and `Li_(2)CO_(3)` are thermally stable. Reason (R ): Both the carbonates are salts of large cations and large anions.A. If both (A) and (R ) are correct and (R ) is the correct explanation of (A).B. If both (A) and (R ) are correct, but (R ) is not the correct explanation of (A).C. If (A) is correct, but (R ) is incorrect.D. If (A) is incorrect, but (R ) is correct. |
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Answer» Correct Answer - D Correct reason: `Na_(2)CO_(3)` is thermally stable, but `Li_(2)CO_(3)` decomposes on heating. `Li_(2)CO_(3)overset(Delta)rarr Li_(2)O+CO_(2)` Correct reason: `Na_(2)CO_(3)` is thermally stable as large cation, `Na^(o+)`, form a stable compound with larger anion `CO_(3)^(2-)`, whereas `Li_(2)CO_(3)` is unstable as it is a salt of small `Li^(o+)` ion and larger `CO_(3)^(2-)` ion. |
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| 114. |
A sodium fire in the laboratory is extinguished byA. WaterB. PetrolC. AlcoholD. `C CI_(4)` |
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Answer» Correct Answer - D Since sodium does not react with `C CI_(4)`. |
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| 115. |
The magnetic moment of `KO_(2)` at room temperature is ---------- BM.A. `1.41`B. `1.73`C. `2.23`D. `2.64` |
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Answer» Correct Answer - B Magnetic `mu = n sqrt(n(n+2))BM` where n is the number of unpaired electron. `KO_(2)` has 1 (one) unpaired electron `mu = sqrt(1(1+2))BM` `sqrt(3) = 1.73BM` |
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| 116. |
a. Which alkali metal is used as a coolent in nuclear reactor ? b. What is the oxidation state of K in `KO_(2)` ? c. The `E^(Θ)` for `CI_(2)CI^(Θ)` is `+1.36`, for `I_(2)//I^(Θ)` is `+0.53`, for `Ag^(o+)//Ag` is `+0.79`, for `Na^(o+)//Na` is `-2.71` and for `Li^(o+)//Li` is`-3.04`. Arrange the following ionic species in decreasing order of reducing strength. `I^(Θ), Ag, CI^(Θ), Li, Na` d. Why is `KO_(2)` is paramagnetic ? |
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Answer» a. Sodium b. The superoxide species respresented as `O_(2)^(Θ)` . Since the compound is netural, therefore the oxidation state of potassium is +1. c. The order is `LigtNagtI^(Θ)gtAggtCI^(Θ)`. d. The superoxide `O_(2)^(Θ)` is paramagnetic, because of one unpaired electron in `pi^(*)2p` antibonding molecular orbital. |
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| 117. |
`KO_(2)` is used in oxygen cylinders in space and submarines because itA. Asorbs `CO_(2)` and increases `O_(2)` contentB. Elminates moistureC. Absorbs `CO_(2)`D. Produces ozone |
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Answer» Correct Answer - A `4KO_(2)+2CO_(2)rarr 2K_(2)CO_(3)+3O_(2)` |
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| 118. |
`KO_(2)` find use in breathing equipment and safeguards the user to breathe in oxygen generated intermally in the apparatus without being exposed to tocixc fumes ouside. The supply of oxygen is due toA. Slow decomposition of `KO_(2)`B. Reaction of `KO_(2)` with `CO_(2)` in the exhaled airC. Reaction of `KO_(2)` with moisture in the essential airD. Fast decomposition of `KO_(2)` |
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Answer» Correct Answer - B::C `2KO_(2)+CO_(2)rarr K_(2)CO_(3)+(3)/(2)O_(2)` `2KO_(2)+2H_(2)O rarr 2KOH+H_(2)O_(2)+O_(2)` |
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| 119. |
`Li_(2)SO_(4)` is not isomorphous with sodium sulphate:A. Due to small size of lithiumB. Due to high coordination number of lithiumC. Due to high ionisation energy of lithiumD. None of the above. |
| Answer» Correct Answer - A | |
| 120. |
LiH, LiF and `Li_(3)N` show exceptional thermal stabilites. Comment. |
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Answer» `Li^(o+)` ion has very small size and has an exceptionally high charge to radius ratio and therefore salts of `Li^(o+)` ion with small anions viz. `H^(Θ)` , `F^(Θ)` and `N^(3-)` are highly stable due to their high lattice energy. `U prop (1)/(r^(o+)+r_(Θ))` Thus LiH, LiF and `Li_(3)N` show exceptionally high thermal stability. |
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| 121. |
Assertion (A): Lithium reacts with oxygen to form `Li_(2)O`, but potassium reacts with oxygen to form `KO_(2)`. Reason (R ): Potassium is more reactive than lithium.A. If both (A) and (R ) are correct and (R ) is the correct explanation of (A).B. If both (A) and (R ) are correct, but (R ) is not the correct explanation of (A).C. If (A) is correct, but (R ) is incorrect.D. If (A) is incorrect, but (R ) is correct. |
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Answer» Correct Answer - B Correct reason: `Li^(o+)` ion having smaller size forms a stable oxide with small `O^(2-)` ion, whereas large `K^(o+)` ion forms a stable oxide with large `O_(2)^(2-)` ion. |
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