Waec Chemistry 2019 Past Questions and Answers

Question 21:

• WAEC 2019

Vinegar is an aqueous solution of?

A. Hydrochloric acid
B. Ethanedioc acid
C. Ethanoic acid
D. Hydrofluoric acid

Question 22:

• WAEC 2019

which of the following solutions containing one mole per dm\(^3\) of the compound would have the lowest PH?

A. Ethanoic acid
B. Hydrochloric acid
C. Sodium chloride
D. Sodium hydrogentrioxocarbonate(iv)

Question 23:

• WAEC 2019

A sample of air was bubbled into water. The PH of the water slowly changed from 7 to 6. Which of the following gases in the samples caused the change?

A. Carbon(iv)oxide
B. Carbon(ii)oxide
C. Nitrogen
D. Oxygen

Question 24:

• WAEC 2019

The most suitable indicator for the reaction between NaOH and HCOOH is?

A. Bromocresol
B. Methyl orange
C. Methyl red
D. Phenolphthalein

Question 25:

• WAEC 2019

consider the following reaction equation: 2Al(OH)\(_3\) + 3H\(_2\)SO\(_4\) →Al\(_2\)(SO4)\(_3\)(aq)+6H\(_2\)O. How many moles of tetraoxosulphate(vi)acid is needed to produce 0.5mol of aluminium tetraoxosulphate(vi)?

A. 0.5
B. 1.0
C. 1.5
D. 3.0