Chemistry

Question 1

1The oxidation number of nitrogen in NH₄⁺ is

Hard

A. −3 B. −4 C. +3 D. +5

Question 2

2A carbonate reacts with an acid to give a salt, water and

Easy

A. carbon dioxide B. ammonia C. oxygen D. hydrogen

Question 3

3An acid salt is formed when

Hard

A. a base is in excess B. the replaceable hydrogen is partly replaced C. water is removed D. all hydrogen is replaced

Question 4

4The pH of 0.01 M HCl is

Hard

A. 12 B. 2 C. 1 D. 0.01

Question 5

5An alkali is a base that

Easy

A. never reacts with acids B. dissolves in water C. has a pH below 7 D. is always solid

Question 6

6The pH of a neutral solution at 25 °C is

Easy

A. 1 B. 14 C. 0 D. 7

Question 7

7What is the oxidation number of manganese in KMnO₄?

Medium

A. +6 B. +7 C. +4 D. +2

Question 8

8How many coulombs are needed to liberate 1.12 dm³ of hydrogen at s.t.p.? (F = 96,500 C)

Hard

A. 19,300 C B. 9,650 C C. 4,825 C D. 96,500 C

Question 9

9The gas produced at the cathode during electrolysis of dilute sulphuric acid is

Easy

A. hydrogen B. oxygen C. sulphur dioxide D. chlorine

Question 10

10The mass of copper deposited by 0.2 mol of electrons (Cu = 64) is

Hard

A. 64 g B. 3.2 g C. 12.8 g D. 6.4 g