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Hydrogen · Question 9

NEET 2016 (Phase 1)Multiple CorrectEasy📈 Topic in 38% papers+4−1
1

Which of the following statements about hydrogen is incorrect?

  1. Hydronium ion, H3O+ exists freely in solution.
  2. Dihydrogen does not act as a reducing agent.
  3. Hydrogen has three isotopes of which tritium is the most common.
  4. Hydrogen never acts as cation in ionic salts.

Answer

(2) Dihydrogen does not act as a reducing agent., (3) Hydrogen has three isotopes of which tritium is the most common.

Solution

(1) A free proton (H+) cannot exist in water; it combines with a water molecule to form the hydronium ion H3O+, which exists in solution. Correct.

(2) As per NCERT, dihydrogen is a reducing agent, e.g. it reduces metal oxides: CuO + H2 Cu + H2O. Incorrect.

(3) Hydrogen has three isotopes: protium, deuterium and tritium. Protium is the most common (about 99.985%), while tritium is radioactive and occurs only in traces. Incorrect.

(4) H+ (a bare proton) is too small to exist as a cation in an ionic lattice, so hydrogen does not act as a cation in ionic salts. Correct.

The incorrect statements are (2) and (3).

Answer: (2), (3)

Out of syllabusNEET 2016 (Phase 1)

Keep practising — Hydrogen

2

(I) H2O2 + O3 H2O + 2O2 (II) H2O2 + Ag2O 2Ag + H2O + O2 Role of hydrogen peroxide in the above reactions is respectively

  1. oxidizing in (I) and reducing in (II)
  2. reducing in (I) and oxidizing in (II)
  3. reducing in (I) and (II)
  4. oxidizing in (I) and (II)
AIPMT 2014
3

Some statements about heavy water are given below: Which of the above statements are correct?

  1. (i) and (ii)
  2. (i), (ii) and (iii)
  3. (ii) and (iii)
  4. (i) and (iii)
Out of syllabusAIPMT 2010 (Mains)
4

Which one of the following molecular hydrides acts as a Lewis acid?

  1. NH3
  2. H2O
  3. B2H6
  4. CH4
AIPMT 2010 (Prelims)
5

The structure of H2O2 is

  1. spherical
  2. non-planar
  3. planar
  4. linear
Out of syllabusAIPMT 2003
6

The life span of atomic hydrogen is

  1. fraction of one second
  2. one year
  3. one hour
  4. one day
Out of syllabusAIPMT 2000

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