UNN Chemistry 2009/2010 Past Questions

Practice each question, then open it to see the full details.

Question 1

The presence of NaCl in ice will

A.lower the boiling point of NaCl
B.increase the melting point of NaCl
C.make NaCl impure
D.lower the melting point of ice

Objective

Question 2

What are the values of x, y and z in the equation below?
xNH₃ + yO₂ ---> zNO + 6H₂O

A.2, 3, 4
B.4, 5, 4
C.6, 5, 4
D.2, 3, 4

Objective

Question 3

Calculate the volume of CO₂, measured at s.t.p. produced on heating 250g of potassium hydrogen trioxocarbonate(IV) strongly (K = 39, H = 1, C = 12, O = 16)

A.28 dm³
B.2.8 dm³
C.5.6 dm³
D.11.2 dm³

Objective

Question 4

The boiling points of water, ethanol, methylbenzene and butan-2-ol are 373.0K, 351.3K, 383.6K and 372.5K respectively. Which liquid has the highest vapour pressure at 323.0K?

A.Water
B.Methylbenzene
C.Ethanol
D.Butan-2-ol

Objective

Question 5

The conclusion from Rutherford's alpha-scattering experiment is that

A.Atoms are mostly empty space with a small nucleus
B.Emissions from radioactive substances consist of three main components
C.There is a nuclear pull on orbital electrons
D.Electrons are deflected by both magnetic and electric fields

Objective

Question 6

Elements P, Q and R have atomic numbers 9, 16 and 20 respectively. Which of them would gain electron(s) during ionic bonding?

A.Q and R
B.P and R
C.P and Q
D.P, Q and R

Objective

Question 7

Which of the following has the lowest pH?

A.5cm³ of M/10 HCl
B.10cm³ of M/10 HCl
C.20cm³ of M/8 HCl
D.15cm³ of M/2 HCl

Objective

Question 8

Which of the following is an acid salt?

A.(NH₃)₂CO₃
B.CHCOONa
C.KHSO₄
D.MgSO₄.7H₂

Objective

Question 9

CrO²⁺ + 14H^- + 6I ----> 2Cr²⁺ + 3I₂ + 7H₂O
The change in the oxidation number of oxygen in the equation above is

Objective

Question 10

During the electrolysis of CuSO₄ solution using Platinum electrodes, which of the following occurs?

A.Acidity increases at the cathode
B.Oxygen is liberated at the cathode
C.pH decreases at the cathode
D.pH of solution decreases

Objective

Question 11

Which of the following ions is a pollution in drinking water even in trace quantities?

A.Ca²⁺
B.Pb²⁺
C.Mg²⁺
D.Fe³⁺

Objective

Question 12

The solubility of a salt of molar mass 100g at 20°C is 0.34mol/dm³. If 3.4g of that salt dissolved completely in 250cm³ of water at that temperature. The resulting solution is

A.a suspension
B.saturated
C.unsaturated
D.supersaturated

Objective

Question 13

Catalyst is important in chemical industry in that

A.It affects the purity of the products
B.It affects the quantity of the products
C.It increases the time for reaching equilibrium
D.Bond breaking is slowed down

Objective

Question 14

An alkanoic acid has a molecular mass of 88. Name the acid. (C = 12, O = 16, H = 1)

A.Propanoic acid
B.Butanoic acid
C.Pentanoic acid
D.But-2-ionic acid

Objective

Question 15

Ethyne undergoes the following reactions except

A.Polymerization
B.Addition
C.Substitution
D.Etherification

Objective