Chemistry Past Questions and Answers

Methanoic acid mixes with water in all proportions and has about the same boiling point as water which of the following methods would you adopt to obtain pure water from a mixture of stand, water and methanoic acid?

A Fractional distillation
B Filtration followed by distillation
C Neutralization with sodium hydroxide followed by distillation
D Esterification with ethanol followed by distillation
E Neutralization with sodium hydroxide followed by filtration

Question 117:

Which of the following statements applies during the electroysis of sodium hydroxide sodium hydroxide solution using platinum electrodes?

A Na<sup style='font-size: smaller;'>+</sup> ions are discharged at the cathode
B Hydrogen ions are discharged at the anode
C The concentration of sodium hydroxide decrease at both electrode compartments
D The concentration of sodium hydroxide increases at the cathode only
E The concentration of sodium hydroxide increases at the anode only

Question 118:

Which of the following statements is true? When the potassium atom forms its ion

A It gains one electron and becomes neutral
B Its atomic number decreases
C It achieves electronic configuration of orgon
D It loses one proton
E It loses one neutron

Question 119:

Which of the following contains two amphoteric oxides?

A Sodium oxide, Zinc oxide , Magnesium oxide
B Aluminium oxide, Calcium oxide, Zinc oxide
C Potassium oxide, Lithium oxide, Carbon monoxide
D Silver oxide, Lead oxide, Sodium oxide
E Sulphur dioxide, Aluminium oxide, Carbon monoxide

Question 120:

Helium atoms are chemically unreactive because

A There are no electrons around the nucleus
B The number of protons equals the number of electrons
C There are equal number of protons and neutrons in the nucleus
D The outer electron shell is completely filled
E The atoms contain only protons