A 2.00 g mixture of Na2CO3 and NaHCO3 is heated to constant mass and loses 0.31 g (Na2CO3 does not decompose). What is the percentage by mass of NaHCO3 in the mixture? (H = 1, C = 12, O = 16, Na = 23)

JEE Advanced levelSingle correct optionDifficulty 3 of 3sb019

A $2.00 g$ mixture of $Na X_{2} CO X_{3}$ and $NaHCO X_{3}$ is heated to constant mass and loses $0.31 g$ ( $Na X_{2} CO X_{3}$ does not decompose). What is the percentage by mass of $NaHCO X_{3}$ in the mixture? (H = 1, C = 12, O = 16, Na = 23)

2 NaHCO X_{3} Na X_{2} CO X_{3} + H X_{2} O + CO X_{2}

168 g

NaHCO X_{3}

loses

18 + 44 = 62 g

. Mass of

NaHCO X_{3}

0.31 \times 168/62 = 0.84 g

. Percentage =

0.84/2.00 \times 100 = 42%