NECO Chemistry Past Questions & Answers - Page 26

126.

Which method is NOT used to determine rate of a reaction?

A.

change in amount of precipitate formed

B.

change in equilibrium constant

C.

change in intensity of colour

D.

change in pH values.

E.

change in total gas pressure

Correct answer is B

No explanation has been provided for this answer.

127.

Ethanol is a product of fermentation of simple sugars. Which method is used to separate ethanol from the other products?

A.

boiling off the ethanoic

B.

filtration

C.

fractional crystallisation

D.

fractional distillation

E.

isomerisation

Correct answer is D

No explanation has been provided for this answer.

128.

To test for the presence of chloride ions in ion, correct sequence of reagents to use is

A.

Ba(NO3)2(aq) then HNO3(aq).

B.

HCl(aq) then Ba(NO3)2(aq).

C.

HCl(aq) then Ag3(aq).

D.

HNO3(aq) then fresh FeSO4(aq).

E.

HNO3(aq) then AgNO3(aq).

Correct answer is E

No explanation has been provided for this answer.

129.

NaCl(s) does NOT conduct electricity, but N(aq) does. This is because

A.

NaCl(s) is non-ionic but NaCl(aq) is ion

B.

NaCl(aq) contains mobile electrons, where absent in NaCl(s).

C.

NaCl(aq) contains mobile ions which Nacl,) does not contain.

D.

NaCl(s) ionizes partiality while NaCl(aq) iodizes completely.

E.

NaCl(s) decomposes when heated but NCl(aq) is stable to heat.

Correct answer is C

No explanation has been provided for this answer.

130.

The green colour solution of an Fe2 salt changes to a brown solution of an Fe3+ salt by

A.

conversion

B.

elimination

C.

oxidation

D.

reduction

E.

substitution

Correct answer is C

No explanation has been provided for this answer.