Which of the following can be found as pollutants in the drinking water in some parts of Indians?
1.  Arsenic                                2. Sorbitol
3.  Fluoride                               4. Formaldehyde
5.  Uranium
Select the correct answer using the code given below.

• 1  and   3

• 2,  4  and 5

• 1,   3  and 5

• All of these

172.

Most commonly used bleaching agent is

• alcohol

• chlorine

• sodium chloride

• carbon dioxide

What happens when a drop of glycerol is added to crushed KMnO₄ spread on a paper?

• The paper ignites

• There is a crackling sound

• There is a violent explosion

• There is no reaction

It is easy to burst a gas-filled balloon with a needle than with a nail. It is because

• nail is more longer than needle

• needle exerts more pressure than nail on the balloon

• gas is reactive with the needle

• nail exerts more pressure than needle on the balloon

Hydrogen peroxide is an effective sterilizing agent. Which one of the following product results when it readily loses active oxygen?

• Water

• Hydrogen

• Nasant Hydrogen

• Ozone

Match the following:

• A - 2,   B - 4,  C - 1,   D - 3

• A - 4,  B - 4,   C - 1,   D - 3

• A - 4,  B - 1,  C - 3,  D - 2

• A - 4,   B - 1,  C - 2,  D - 3

The percentage of nitrogen present in ammonium sulphate is

• 30.5%

• 18%

• 21%

• 25%

Stains of rust on clothes can be removed by

• alcohol

• H₂O₂

• oxalic acid

• petrol

Acceptable 'Noise Pollution Level' in India range between

• 70 - 100 db

• 10 - 15 db

• 16 - 35 db

• 40 - 45 db

Steel is more elastic than rubber because it

• is deformed very easily

• is harder than rubber

• required larger deforming force

• is never deformed