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NECO Chemistry Past Questions & Answers - Page 24

116.

B is an isotope of the element 23892Ur. The isotope B has

A.

46 protons and 119 neutrons

B.

92 protons and 92 neutrons

C.

92 protons and 146 neutrons

D.

92 protons and 238 neutrons

Correct answer is C

No explanation has been provided for this answer.

117.

The number of hydrogen ions in 1.0dm6.00x103 of a 0.25 mole dm6.00x10-3 tetraoxosulphate(Vl) acid solution is
[Avogadro constant = 6.0 x 1 0]

A.

1.45x1023

B.

1.50 x l023

C.

3.00x1023

D.

3.15x1023

E.

6.00x1023

Correct answer is B

No explanation has been provided for this answer.

118.

Chlorine is used in water purification because it

A.

bleaches impurities in the water

B.

decolorizes water

C.

destroys bacteria

D.

is extremely soluble in water

E.

is pleasant tasting

Correct answer is C

No explanation has been provided for this answer.

119.

Which statement is NOT true about the composition of starch?

A.

It contains only the atoms of carbon, hydrogen oxygen

B.

It is a polysaccharide

C.

Its empirical formula is C2H20.

D.

It is made from the monomerC6H12O6.

E.

The hydrogen and oxygen atoms are in the ratio 2:1.

Correct answer is C

No explanation has been provided for this answer.

120.

Which compound is a component of baking powder?

A.

Na2CO3

B.

Na2SO4

C.

KH2CO3

D.

NaHCO3

E.

NaHSO4

Correct answer is D

No explanation has been provided for this answer.