4g equimolar mixture of NaOH and $\mathrm{Na}_{2} \mathrm{CO}_{3}$ contains xg of NaOH and y g of $\mathrm{Na}_{2} \mathrm{CO}_{3}$. The value of $x$ is ______ g.(Nearest Integer)

JEE Main · 2021 · 20 Jul 2021 · Shift 2 · Some Basic Concepts of Chemistry

4g equimolar mixture of NaOH and

Na_{2} CO_{3}

contains xg of NaOH and y g of

Na_{2} CO_{3}

. The value of

x

is ______ g.(Nearest Integer)

Answer: 1

Let the number of moles of each compound be

n

.

Molar mass of NaOH = 40 g/mol
Molar mass of

Na_{2} CO_{3}

= 106 g/mol

Mass of NaOH:

x = 40 n

Mass of

Na_{2} CO_{3}

y = 106 n

Total mass:

x + y = 4

40 n + 106 n = 4

146 n = 4

n = 4/146 = 2/73

x = 40 \times (2/73) = 80/73 \approx 1.10

g

To the nearest integer,

x = 1

JEE Main · 2021 · 20 Jul 2021 · Shift 2 · Integer answer