Waec Chemistry 2020 Past Questions and Answers

Question 6:

• WAEC 2020

What quantity of electrons is lost when one mole of iron (II) ions is oxidized to iron (III) ?

A. 0 mole3 moles
B. I mole
C. 2 moles

Question 7:

• WAEC 2020

What is the mass of silver deposited when 24,125 C of electricity is passed through a solution or silver salt.
[Ag = 108, IF = 96,500 C ]

A. 432g
B. 108g
C. 54g
D. 27g

Question 8:

• WAEC 2020

Equal masses of calcium trioxocarbonate(iv) were added to dilute hydrochloric acid at the temperature specified. Under which of the following conditions would the reaction be slowest?

A. Calcium trioxocarbonate ( iv ) chips a 20°C
B. CalcIum trioxocarbonate (IV) chips at 40°C
C. Calcium trioxocarbonate (IV) powder at 20'C
D. Calcium trioxocarbonate (IV) powder at 40'C

Question 9:

• WAEC 2020

The high solubility of ethanol in water is due to?

A. Its low boiling point.
B. Its low freezing point.
C. Its covalent nature
D. Hydrogen bonding

Question 10:

• WAEC 2020

Which of the following pairs of properties of alkali metals decreases down the group?

A. First ionization energy and reactivity
B. Melting point and atomic radius
C. Reactivity and electronegativity
D. First ionization energy and melting point