Question

A sample of $NaCl{{O}_{3}}$ is converted by heat to NaCl with a loss of 0.16 g of oxygen. The residue is dissolved in water and precipitated as AgCl. The mass of AgCl in grams obtained will be. Given molar mass of AgCl = 143.5 g/mol.
(A) 0.35
(B) 0.41
(C) 0.48
(D) 0.54

Answer 1

Hint: The molar mass can be calculated by adding the individual atomic masses of all the elements present in the compounds. In case of multiple atoms of the same elements in a compound multiply the number of atoms with the atomic mass of the element and then add with the atomic masses of the other elements.

Complete step by step solution:
Given in the question: A sample of $NaCl{{O}_{3}}$ is converted by heat to NaCl with a loss of 0.16 g of oxygen
Molar mass of AgCl = 143.5 g/mol
We know that the molar mass of oxygen is = 32 g/mol
And there is a loss of 0.16g of oxygen. The number of moles of oxygen can be calculated by dividing the given mass of oxygen with the molar mass of oxygen.
The number of moles of oxygen = $\dfrac{0.16}{32}=0.005mol$
The reaction involved in the given question is:
\[2NaCl{{O}_{3}}\to 2NaCl+3{{O}_{2}}\]
And, 3 moles of oxygen = 2 moles of $NaCl{{O}_{3}}$= 2 moles of silver chloride
0.005 moles of oxygen will give = $0.005(\dfrac{2}{3})=0.00333$ moles of silver chloride i.e. AgCl
Molar mass of AgCl is given as = 143.5 g/mol
The mass of silver chloride obtained will be = $(143.5)(0.00333)$ = 0.48 g

Hence the correct answer is option (C) i.e. the mass of AgCl in grams obtained is 0.48g.

Note: While calculating the molar mass carefully to multiply the number of atoms of the elements with its atomic masses. Failure to do so will definitely lead to an incorrect answer.