A sample of a compound contains ​0.300 mol​ ​of carbon​ and ​1.20 mol​ ​of hydrogen​.

1st, 3rd and 4th.

Explanation:

There are few salts which have so much large atomic or molecular radii that the intermolecular forces of solvent are unable to get them separated.

Sodium sulphate (Na2SO4) solution is when mixed with Ba(NO3)2, BaSO4 precipitates out having white color.

Ammonium chloride (NH4Cl) solution when mixed with Magnesium Nitrate (Mg(NO3)2) solution, no precipitates are formed and this is a reversible reaction.

Potassium floride (KF) solution when mixed with Barium Nitrate (Ba(NO3)2) solution, BaF2 precipitates out having white color.

Magnesium chloride (MgCl2) solution is when mixed with Sodium carbonate (Na2CO3) solution, MgCO3 precipitates out having white color.