Lead pipes can be used for:

1.  soft water

2.  hard water

3.  both hard and soft water

4.  none of the above

Ordinary glass is:

1.  sodium silicate

2.  copper silicate

3.  calcium silicate

4.  a mixture of calcium and sodium silicates with silica

Synthesis gas is a mixture of:

1.  steam and carbon monoxide

2.  carbon monoxide and nitrogen

3.  hydrogen and carbon monoxide

4.  hydrogen and methane

The substance used to impart green colour to glass is:

1.  ${\mathrm{Cu}}_2\mathrm{O}$

2.  $\mathrm{CdS}$

3.  ${\mathrm{MnO}}_2$

4.  ${\mathrm{Cr}}_2{\mathrm{O}}_3$

The percentage of lead in a lead pencil is-

1.  20

2.  0

3.  80

4.  70

Tin cry refers to- 

1. Conversion of white to grey tin

2. Tin plating

3. Conversion of white tetrahedral tin to white rhombohedral tin

4. Emission of sound while bending a tin rod

Carbogen is:

1.  mixture of ${\mathrm{O}}_2+5-10\% {\mathrm{CO}}_2$

2.  used by pneumonia patients for respiration

3.  used by victims of $\mathrm{CO}$ for respiration

4.  all of the above

If a person is injured by the shot of a gun and all the pellets could not be removed, it may cause poisoning by:

1.  Hg

2.  Pb

3.  Fe

4.  As

The carbon of microphones used in public address systems is:

1.  graphite

2.  charcoal

3.  coke

4.  lamp black

Which element of group 14 forms only one hydride?

1.  C

2.  Si

3.  Sn

4.  Pb