WAEC Chemistry Past Questions & Answers - Page 194

966.

The electronic configuration of an element is 1\(s^2\) 2\(s^2\) 2\(p^6\) 3\(s^2\) 3\(p^3\). Where is the element located in the periodic table?

A.

Group lll, period 3

B.

Group lll, period 5

C.

Group V, period 3

D.

Group V, period 5

Correct answer is C

the element belongs to group 5, since we have two coefficients that are the same we simply add the powers that give 5. while the highest coefficient gives the period that is 3.

therefore, the element is found in group 5 period 3.

967.

Which of the following statements about soapless detergents is correct? They

A.

lather readily with hard water

B.

increase the surface tension of water

C.

cause hydrolysis of salts in water

D.

from a curdy precipitate with soft water

Correct answer is A

No explanation has been provided for this answer.

968.

The following compounds are hydrocarbons except

A.

methylpropanoate

B.

2-methylbutane

C.

benzene

D.

cyclohexane

Correct answer is A

No explanation has been provided for this answer.

969.

When alkynes are hydrogenated completely, they produce compounds with the general molecular formula

A.

C nH n

B.

C nH 2n+2

C.

CnH 2n

D.

CnH2n-2

Correct answer is B

when alkyne(\(C_nH_{2n - 2}\)) are hydrogenated completely, alkanes( \(C_nH_{2n + 2}\)) are produced.

970.

Which of the following compounds can be represented by the molecular formula C2H6O?

A.

Propanel

B.

Ethanol

C.

Methanoic acid

D.

Glucose

Correct answer is B

No explanation has been provided for this answer.