WAEC Chemistry Past Questions & Answers - Page 44

216.

Vinegar is an aqueous solution of?

A.

Hydrochloric acid

B.

ethanedioc acid

C.

ethanoic acid

D.

hydrofluoric acid

Correct answer is C

Vinegar is an aqueous solution of acetic acid and trace compounds that may include flavorings

217.

What is the solubility of a salt X at 25ºC if the saturated solution of the salt contains 0.28g in 100cm\(^3\) of the solution in mol\dm\(^3\)? 

[ X = 56.0g ]

A.

0.05

B.

0.10

C.

2.60

D.

2.80

Correct answer is A

(mass / molar mass) X (1000 / vol )

(0.28 / 56.0) X (1000 / 100 )

= 2.8 / 56 

= 0.05 mol\dm\(^3\)

218.

The properties of a good primary standard solution include the following except?

A.

High molecular mass

B.

low molecular mass

C.

high degree of purity

D.

readily available

Correct answer is B

Properties of a good standard solution

  • High purity.
  • Stability (low reactivity)
  • Low hygroscopicity (to minimize weight changes due to humidity)
  • High equivalent weight (to minimize weighing errors)
  • Non-toxicity.
  • Ready and cheap availability.
  •  High molecular mass

219.

The name of the compound CH\(_3\)C(CH\(_3\))\(_2\)CH\(_2\)CH\(_2\)CH\(_3\)

A.

2 - methyl butane

B.

2,2 - dimethyl butane

C.

2 - methyl pentane

D.

2,2 - dimethyl pentane

Correct answer is D

- The longest chain has five carbon atoms i.e PENT

- with two methyl attached to the second carbon atom 

220.

Which of the following compounds has coordinate bonds in its structure?

A.

Al\(_2\)Cl\(_6\)

B.

MgCl\(_2\)

C.

AgCl

D.

NaCl

Correct answer is A

Aluminum chloride (Al2Cl6) has coordinate dative bonding