Waec Chemistry 2021 Past Questions and Answers

Question 26:

• WAEC 2021

Which of the following pairs of compounds would form a precipitate when their aqueous solutions are mixed?

A. NaCl and KNO\(_{3}\)
B. KCL and NaNO\(_{3}\)
C. K\(_{2}\)SO\(_{4}\) and BaCl\(_{2}\)
D. NH\(_{4}\)NO\(_{3}\) and CO\(_{3}\)

Question 27:

• WAEC 2021

Study the graphs below and use them to answer the question below



Which of the following illustrates the variation of the rate of evolution of gas from a given length of magnesium ribbon (y-axis) with an increase in the concentration of the added (x-axis)?

A. I
B. II
C. III
D. IV

Question 28:

• WAEC 2021

The reactivity of fluorine is high because of ____________

A. Its high electronegativity
B. The small size of the fluorine atom
C. The availability of d-orbitals
D. The strong F-F bond

Question 29:

• WAEC 2021

How many coulombs of electricity would liberate 1.08g of Ag from a solution of silver salt?
[Ag = 108.0; 1F = 96500 C]

A. 96500 C
B. 9650 C
C. 965 C
D. 9.65 C

Question 30:

• WAEC 2021

The Bohr model of the atom proposed the existence of ____________

A. The nucleus
B. Electron shells
C. Nucleons
D. Neutrons