Chemistry Past Questions and Answers

20 cm³ of 0.09 mol dm³ solution of tetraoxosuiphate (Vi) acid requires 30cm³ of sodium hydroxide solution for complete neutralization. The molar concentration of sodium hydroxide is [H = 1; S = 32; 0 = 16; Na = 23]

A 0.03 mol dm³
B 0.12 mol dm³
C 0.27 mol dm³
D 0.45 mol dm³
E 0.90 mol dm³

Question 22:

The decreasing order of the oxidising power of the halogens is ____________

A Br>I>Cl>F
B F>I>Cl>Br
C F>Cl>Br>l
D I>Br>Cl>F
E Cl>Br>F>I

Question 23:

Which statement BEST describes the process of oxidation?

A Addition of hydrogen
B Loss of oxygen
C Decrease in oxidation number
D Loss of electrons
E Gain of elections.

Question 24:

Animal charcoal differs from wood charcoal in that it ____________

A Has a dark colour
B Has a high carbon content
C Is a good absorbent
D Is crystalline.
E Is rich in phosphate content

Question 25:

The atomic number of iron is 56. The number of unpaired electrons in the Fe3+ ion is ____________