An inorganic salt gave the following percentage composition:
Na = 23.11, S= 40.51 and O=30.38
Calculate the empirical formula of the salt.
Answer & explanation
Correct answer: option 3
The correct answer is option 3. Na2S2O3.
\(\text{Calculation of the empirical formula : }\)
| Element | Symbol |
Percentage of element |
Atomic mass of the element |
moles of the element =\(\frac{Percentage}{\text{Atomic mass}}\) \(\text{Ralative number of moles}\) |
Simplest molar ratio |
Simplest whole number molar ratio |
| Sodium | Na | 29.11 | 23 | \(\frac{29.11}{23}\text{ = 1.266}\) | \(\frac{1.266}{1.266}\text{ = 1}\) | 2 |
| Sulphur | S | 40.51 | 32 | \(\frac{40.51}{32}\text{ = 1.266}\) | \(\frac{1.266}{1.266}\text{ = 1}\) | 2 |
| Oxygen | O | 16 | 16 | \(\frac{30.38}{16}\text{ = 1.897}\) | \(\frac{1.89}{1.266}\text{ = 1.5}\) | 3 |
∴ \(\text{The Empirical formula is =}Na_2S_2O_3\)