General Knowledge - 6

1) pH of water is

A: 6.4

B: 7.4

C: 8

Ans: 7.4

2) Ruby is an oxide of ______

A:  silver

B: gold

C: aluminium

Ans: aluminium

3) Air contains maximum amount of ________

A: oxygen

B: nitrogen

C: hydrogen

Ans: nitrogen

4) The element used in lead pencils is _______

A: zinc

B: lead

C: carbon

Ans: carbon

5)  The acid present in lemon is _______

A: lactic acid

B:  tartaric acid

C: citric acid

Ans: citric acid