Question

The sodium salt of methyl orange has 7% sodium. What is the minimum molecular weight of the compound?

Answer 1

Let M be the minimum molecular weight of the compound.

7% of the compound is sodium. It is equal to 

$\sf \frac{100}7×M=0.07M g$sodium in 1 mole of compound.

At least, 1 mole of Na (Sodium) will be present in 1 mole of compound.

• 1 mole of sodium weighs 23 g.

Thus, 0.07M=23

$\sf \: M=\frac{23}{0.07} \\ \sf \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: =\underline{\boxed{\bold{\frak{329 g/mol}}}}\pink\bigstar$

Thus, the minimum molecular weight of the compound is 329 g/mol.

Thank you!

@itzshivani

Answer 2

Answer :-

Minimum molecular weight of the compound is 328.57 g/mol .

Explanation :-

We have :-

→ Percentage of Sodium = 7 %

→ Molar mass of Sodium = 23 g/mol

______________________________

Let's assume that mass of the Sodium salt of methyl orange comprising of 7% Sodium is 100 grams . So, mass of sodium in the compund will be 7 grams .

In order to get the minimum molecular weight of the compound, we have to assume that there is only one mole of sodium atoms in it which weighs 23 grams .

______________________________

∵ 7 g of Sodium = 100 g of compound

∴ 23 g of Sodium :-

= (23 × 100)/7

= 2300/7

= 328.57 g of compound