CBSE Class 11 Chemistry HOTs Hydrogen

Question. When same amount of zinc is treated separately with excess of sulphuric acid and excess of sodium hydroxide solution the ratio of volumes of hydrogen evolved is
(a) 1 : 1
(b) 1 : 2
(c) 2 : 1
(d) 9 : 4
Answer : A

Question. 2 g of aluminium is treated separately with excess of dilute H2SO4 and excess of NaOH. The ratio of the volumes of hydrogen evolved is
(a) 2 : 3
(b) 1 : 1
(c) 2 : 1
(d) 1 : 2
Answer : B

Question. Consider the following statements :
1. Atomic hydrogen is obtained by passing hydrogen through an electric arc.
2. Hydrogen gas will not reduce heated aluminium oxide.
3. Finely divided palladium adsorbs large volume of hydrogen gas
4. Pure nascent hydrogen is best obtained by reacting Na with C₂H₅OH
Which of the above statements is/are correct ?
(a) only 1
(b) only 2
(c) 1, 2 and 3
(d) 2, 3 and 4
Answer : C

Question. Which hydride is an ionic hydride?
(a) H₂S
(b) TiH_1.73
(c) NH₃
(d) NaH
Answer : D

Question. The reagent commonly used to determine hardness of water titrimetrically is
(a) oxalic acid
(b) sodium thiosulphate
(c) sodium citrate
(d) disodium salt of EDTA
Answer : D

Question. Pure water can be obtained from sea water by
(a) centrifugation
(b) plasmolysis
(c) reverse osmosis
(d) sedimentation
Answer : C

Question. Chemical A is used for water softening to remove temporary hardness. A reacts with sodium carbonate to generate caustic soda. When CO₂ is bubbled through a solution of A, it turns cloudy. What is the chemical formula of A.
(a) CaCO₃
(b) CaO
(c) Ca(OH)₂
(d) Ca(HCO₃)₂
Answer : C

Question. Which of the following statements do not define the characteristic property of water “Water is a universal solvent”
(a) It can dissolve maximum number of compounds
(b) It has very low dielectric constant
(c) It has high liquid range
(d) None of these
Answer : B

Question. The amount of H₂O₂ present in 1 litre of 1.5 N H₂O₂ solution, is
(a) 25.5 g
(b) 3.0 g
(c) 8.0 g
(d) 2.5 g
Answer : A

Question. The volume strength of 1.5 N H₂O₂ solution is
(a) 8.4
(b) 8.0
(c) 4.8
(d) 3.0
Answer : A

Question. In lab H₂O₂ is prepared by
(a) cold H₂SO₄ + BaO₂
(b) HCl + BaO₂
(c) conc. H₂SO₄ + Na₂O₂
(d) H₂ + O₂
Answer : A

Question. The strength in volumes of a solution containing 30.36 g/L of H₂O₂ is
(a) 10 V
(b) 5 V
(c) 20 V
(d) None of these
Answer : A

Question. 20 Volume H₂O₂ solution has a strength of about
(a) 30%
(b) 6%
(c) 3%
(d) 10%
Answer : B

Question. H₂O₂ is a
(a) weak acid
(b) weak base
(c) neutral
(d) None of these
Answer : A

Question. H₂O₂ → 2H+ + O₂ + 2e– ; E° = –0.68 V. This equation represents which of the following behaviour of H₂O₂ ?
(a) Reducing
(b) Oxidising
(c) Acidic
(d) Catalytic
Answer : A

Question. Heavy water reacts respectively with CO₂, SO₃, P₂O₅ and N₂O₅ to give the compounds
(a) D₂CO₃, D₂SO₄, D3PO₂, DNO₂
(b) D₂CO₃, D₂SO₄, D₃PO₄, DNO₂
(c) D₂CO₃, D2SO3, D₃PO₄, DNO₂
(d) D₂CO₃, D₂SO₄, D₃PO₄, DNO₃
Answer : D

Question. A, 6 volume sample of H₂O₂
(a) will contain 6% V/V of H₂O₂
(b) will contain 6% W/V of H₂O₂
(c) would give 6 volumes of oxygen per unit volume of H₂O₂ sample at STP
(d) would give 6 volumes of oxygen per unit weight of H₂O₂ sample at STP
Answer : C

Question. In water-gas shift reaction, hydrogen gas is produced from the reaction of steam with
(a) methane
(b) coke
(c) carbon monoxide
(d) carbon dioxide
Answer : C

Question. Treatment with lime can remove hardness of water caused by
(a) CaCl₂
(b) CaSO₄
(c) Ca(HCO₃)₂
(d) CaCO₃
Answer : C

Question. Permanent hardness of water can be removed by
(a) heating
(b) treating with sodium acetate (CH₃CO₂Na)
(c) treating with Ca(HCO₃)₂
(d) treatment with sodium hexametaphosphate(Na₆P₆O₁₈)
Answer : D

Numeric Value Answer

Question. At room temperature, the ratio of ortho to para hydrogen is n : 1. what is the value of n?
Answer : 3

Question. If 1 L of hard water (contains CaSO₄) requires 0.286 g of washing soda (Na₂CO₃ . 10H₂O) for softening process. What is the hardness of water in ppm?
Answer : 100

Question. 3 Samples of H₂O₂ are labelled as 10 vol., 15 vol. and 20 vol. 100 mL. of each sample is mixed. What is the volume strength of resulting solution?
Answer : 15

Question. Ordinary water contains traces of heavy water. This is about 1part in n ×1000 parts. What is the integer value of n?
Answer : 6

Question. What is the amount of energy released (in KJ) on combustion of 1 g of H₂ gas?
Answer : 143