Waec Chemistry 2021 Past Questions and Answers

Question 36:

• WAEC 2021

Electrovalent compounds normally ____________

A. Have low boiling points
B. Have mobile electrons
C. Conduct electricity in the solid state
D. Dissolve in polar solvent

Question 37:

• WAEC 2021

A coordinate covalent bond could be formed between

A. NH\(_{3}\) and PC/\(_{3}\)
B. BC/\(_{3}\) and A/C/\(_{3}\)
C. BC/\(_{3}\) and NH\(_{3}\)
D. H\(^{+}\) and A/C/\(_{3}\)

Question 38:

• WAEC 2021

Student X titrated 25 cm\(^{3}\) of Na\(_{2}\)CO\(^{3}\) with 0.1 mol dm\(^{-3}\) HCI, using methyl orange as indicator. Student Y carried out the same exercise but used phenolphthalein as an indicator. Which of the following statements about the titration is true?

A. Hydrogen chloride gas was released in the reactions in both titrations
B. The titer values obtained from the titration are equal
C. The tirer value obtained by X is twice that of Y
D. The titer value obtained by Y is twice that of X

Question 39:

• WAEC 2021

What is the concentration of a solution which contains 0.28g of potassium hydroxide in 100 cm\(^{3}\) of solution [KOH = 56]

A. 0.01 mol dm\(^{-3}\)
B. 0.05 mol dm\(^{-3}\)
C. 0.10 mol dm\(^{-3}\)
D. 0.50 mol dm\(^{-3}\)

Question 40:

• WAEC 2021

What is the empirical formula of a hydrocarbon containing 0.160 moles of carbon and 0.640 moles of hydrogen

A. CH\(_{2}\)
B. CH\(_{3}\)
C. CH\(_{4}\)
D. C\(_{2}\)H\(_{4}\)