Chemistry Past Questions and Answers

Question 16 :

• JAMB 2019

A sample of hard water contains some calcium sulphate and calcium hydrogen carbonate. The total hardness may therefore be removed by

A. Boiling the water
B. Adding excess calcium hydroxide
C. Adding a calculated amount of calcium hydroxide
D. Adding sodium carbonate
E. Adding magnesium hydroxide

Question 17 :

• JAMB 2019

During the electrolysis of copper II sulphate between platinum electrodes, if litmus solution is added to the anode compartment,

A. The litmus turns blue but no gas is evolved
B. The litmus turns blue and oxygen is evolved
C. The litmus turns blue and hydrogen is evolved
D. The litmus turns red and oxygen is evolved
E. The litmus turns red and then becomes colourless

Question 18 :

• JAMB 2019

The reaction between an organic acid and an alcohol in the presence of an acid catalyst is known as;

A. Saponification
B. Dehydration
C. Esterification
D. Hydrolysis
E. Hydration

Question 19 :

• JAMB 2019

The IUPAC names of the compounds CH3COOH and CH2=CH2 are respectively;

A. Acetic acid and ethene
B. Ethanoic acid and ethene
C. Methanoic acid and ethylene
D. Ethanol and ethene
E. Acetic acid and ethylene

Question 20 :

• JAMB 2019

If 30cm3 of oxygen diffuses through a porous pot in 7 seconds, how long will it take 60cm3 of chlorine to diffuse through the same pot, if the vapour densities of oxygen and chlorine are 16 and 36 respectively?

A. 9.3 sec
B. 14 sec
C. 21 sec
D. 28 sec
E. 30.3 sec