Chemistry questions and answers

Chemistry Questions and Answers

Learn more about the properties, composition, and structure of substances (elements and compounds) with these Chemistry questions and answers. This Test can be used by students preparing for Chemistry in JAMB, WAEC, NECO or Post UTME.

1,166.

Hydrogen can be displaced from a hot alkaline solution by

A.

Fe

B.

Cu

C.

Ca

D.

Sn

Correct answer is D

Tin dissolves in concentrated solution of alkalis to give trioxostannate(IV) salt and hydrogen.

1,167.

Which of the following ions  requires the largest quantity of electricity for discharge at an electrode?

A.

2.0 mole of Q3+

B.

2.5 mole of R2+

C.

3.0 mole of T-

D.

4.0 mole of Y-

Correct answer is A

2.0 mole of Q3+ ions require the largest quantity of electricity for discharge at an electric. option B,C,D are all carrying a smaller quantity of electricity which not be proven for ant discharge

1,168.

A fixed mass of gas occupies 92cm3 at 3°C. What will be its volume at 18C if the pressure remains constant?

A.

15.3cm3

B.

87.3cm3

C.

2.0cm3

D.

97.0cm3

Correct answer is D

\(\frac{V_{1}}{T_{1}}\) = \(\frac{V_{2}}{T_{2}}\)
\(T_{1}\) = 3 + 273 = 276K
\(T_{2}\) = 18 + 273 = 291K
\(V_{1}\) = \(92cm^{3}\)
\(V_{2}\) = ?
\(V_{2}\) = \(\frac{V_{1}T_{2}}{T_{1}}\)

=\(\frac{92 \times 291}{276}\) 
= \(97.0cm^{3}\)

1,169.

P1V1 = P2V2 supports ?

A.

Charles’s law

B.

Boyles’s law

C.

Graham’s law

D.

Avogadro’s law

Correct answer is B

V = 1/P

cross multiply

K = VP

V1P1 = V2V2

For a fixed amount of an ideal gas kept at a fixed temperature, pressure and volume are inversely proportional. Or Boyle's law is a gas law, stating that the pressure and volume of a gas have an inverse relationship, when temperature is held constant.
The equations supports only Boyle’s law. Option A,C,D are not in support of the equation...

1,170.

Tartaric acid is used industrially to

A.

make baking powder

B.

make fruit juice

C.

remove rust

D.

dry substance

Correct answer is A

A is the correct answer. Tartaric acid is found in cream of tartar, which is used in cooking candies and frostings for cakes. Tartaric acid is also found in baking powder, where it serves as the source of acid that reacts with sodium bicarbonate (baking soda)