Question

Praveen took lead nitrate solution in a test tube and added sodium chloride solution to

it. How will he prove that the reaction satisfies the law of conservation of mass?​

Answer 1

Answer:

$\huge\underline\mathcal\green{AnSWer}$

The residue left on evaporation will mostly be a mixture of three salts.The two definite ones are lead chloride and sodium nitrate formed by the double displacement between sodium chloride and lead nitrate.2NaCl (aq) + Pb(NO3)2 (aq) ——→ PbCl2 (s) + 2NaNO3 (aq)The third constituent will be either the unreacted NaCl or Pb(NO3)2 that is present in excess of the 2:1 molar ratio in which these two salts react as per the above equation.But if NaCl and Pb(NO3)2 are taken in the exact 2:1 molar ratio in the test tube with sufficient water, the contents on evaporation are expected to yield, at least theoretically, a solid mixture having only NaNO3 and PbCl2, in the 2:1 molar ratio. There should not be any unreacted NaCl or Pb(NO3)2 as a third constituent.

Answer 2

Explanation:

These two solutions reacts to form a white insoluble precipitate.

These two solutions reacts to form a white insoluble precipitate. BaCl 2 +Na SO 4 →2NaCl+BaSO 4↓

→2NaCl+BaSO 4↓ This is a double displacement reaction as the two compounds exchange their ions to form to different compounds.