Which of the following is responsible for the Prussian blue colour in Lassaigne’s test for nitrogen?:

$1.<mspace\; width="1em"></mspace>{\mathrm{Na}}_4\left[\mathrm{Fe}{\left(\mathrm{CN}\right)}_6\right]<mspace\; width="1em"></mspace>$
$2.<mspace\; width="1em"></mspace>{\mathrm{Fe}}_4[\mathrm{Fe}{\left(\mathrm{CN}\right)}_6{]}_3$
$3.<mspace\; width="1em"></mspace>{\mathrm{Fe}}_2\left[\mathrm{Fe}{\left(\mathrm{CN}\right)}_6\right]<mspace\; width="1em"></mspace>$
$4.<mspace\; width="1em"></mspace>{\mathrm{Fe}}_3[\mathrm{Fe}{\left(\mathrm{CN}\right)}_6{]}_4$

The latest technique for isolation, purification and separation of organic compounds is -

IUPAC name of the given compound is :

1. 3-Phenylpropane

2. Phenyl-1-butane

3. 2-Benzylethane

4. Propyl benzene

The method that can be used to separate two compounds with different solubilities in a solvent is-
1. Distillation
2. Isolation
3. Fractional crystallization
4. Filtration

Which purification method is suitable for a liquid that decomposes upon boiling?

1. Fractional distillation  
2. Steam distillation
3. Simple distillation 
4. Distillation under reduced pressure

Find the elements that can be detected by Lassaigne's test

1. Nitrogen, Sulphur, Halogens

2. Nitrogen, Cyanides, Sulphur

3. Sodium, Sulphur, Halogens, Phosphorus

4. Nitrogen, Sulphur, Halogens, Phosphorus

Halogen in an organic compound that can be detected by -

Nitric acid is added to sodium extract before adding silver nitrate for testing halogens because:

1. Nitric acid reduces sulphide

2. Nitric acid decomposes NaCN and Na₂S

3. Nitric acid oxidises the organic compound

4. Nitric acid acts as a dehydrating agent

Metallic sodium is fused with organic compounds for testing nitrogen, sulphur, and halogens. The correct reason behind this is: