Question Detail

CHM 101 CHM 101 Past Questions Objective Question
Take CBT

Question

In which reaction does the oxidation number of hydrogen change?
Options
A HCl(aq) + NaOH(aq) → NaCl(aq) + H₂O(l)
B SO₃(g) + H₂O(l) → H₂SO₄(aq)
C CaO(s) + H₂O(l) → Ca(OH)₂(s)
D 2Na(s) + 2H₂O(l) → 2NaOH(aq) + H₂(g)
Correct Answer
Correct Answer

Option D is the correct answer.

Detailed Explanation

In option D, hydrogen in H₂O has oxidation state +1, and in H₂(g) it is 0. So hydrogen is reduced (oxidation number decreases). In the other options, hydrogen remains +1 throughout.

Hint

Look for a reaction where elemental hydrogen (H₂) is formed or consumed.

Question Info

Course: CHM 101
Topic: CHM 101 Past Questions
Type: Objective
Difficulty: Not specified
Question 1192 of 1872
Previous Course Details Next