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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.

456.

A cell shorthand notation can be written as A / A+ // B2+ /B. The double slash in the notation represents the 

A.

electrolyte

B.

electrodes

C.

salt bridge

D.

solid - liquid interface

Correct answer is C

No explanation has been provided for this answer.

457.

Consider the reaction: A + 2B(g) 2C + D(g) (ΔH = +ve)

What will be the effect of decrease in temperature on the reaction?

A.

Rate of backward reaction will increase

B.

The equilibrium constant will shift

C.

Rates of forward and backward reactions are not affected

D.

Rate of forward reaction will increase

Correct answer is A

The given reaction is endothermic, hence, a decrease in temperature will favor the exothermic side which is the backward reaction.

458.

The following are isoelectronic ions except

A.

Na+

B.

Mg2+

C.

Si2+

D.

O2+

Correct answer is C

Two or more ions are said to be isoelectronic if they have the same electronic structure and the same number of valence electrons.

Na+ = 10 electrons = 2, 8

Mg2+ = 10 electrons = 2,8

O2 = 10 electrons = 2,8

Si2+ = 12 electrons = 2,8,2

Si2+ is not isoelectronic with the rest.

459.

The hybridization in the compound CH3CH2CH is

A.

sp3 and sp

B.

sp

C.

sp2

D.

sp3 and sp2

Correct answer is A

The hybridization in a and b is sp3 hybridization while in c and d is sp hybridization.

460.

The electronic configuration of element Z is 1s2 2s2 2p6 3s2 3p1. What is the formula of the compound formed between Z and tetraoxosulphate (VI) ion.

A.

Z3(SO4)2

B.

ZSO4

C.

Z2 SO4

D.

Z2(SO4)3

Correct answer is D

Z = 1s2 2s2 2p6 3s2 3p1

We have Z^{3+} and SO_4 ^{2-}

The reaction : Z^{3+} + SO_4 ^{2-} \to Z_2(SO_4)_3.