Significant figures include all meaningful digits in a number. Use the rules for counting significant figures carefully, especially for decimals and trailing zeros.
Significant figures represent all the digits in a number that are meaningful in terms of precision. They include all non-zero digits, zeros between non-zero digits, and trailing zeros in decimal numbers. Here is the breakdown:
Thus, 0.00253 (option A), 15.0 (option B), and 163 (option C) all have the same number of significant figures, which is 3.
Therefore, the correct answer is option (4).
A substance 'X' (1.5 g) dissolved in 150 g of a solvent 'Y' (molar mass = 300 g mol$^{-1}$) led to an elevation of the boiling point by 0.5 K. The relative lowering in the vapour pressure of the solvent 'Y' is $____________ \(\times 10^{-2}\). (nearest integer)
[Given : $K_{b}$ of the solvent = 5.0 K kg mol$^{-1}$]
Assume the solution to be dilute and no association or dissociation of X takes place in solution.