Question

A student performs titration with different burettes and finds titre value of 25.2ml, 25.25 ml and 25.0 ml. The number of significant figures in the average titre value is:
(A) 3
(B) 4
(C) 6
(D) 8

Answer 1

Significant figures of a number are digits which contribute to the precision of that number. Numbers that do not contribute any precision and should not be counted as a significant number are:
1.leading or trailing zeros (those are place holders)
2.digits that are introduced by calculations that give the number more precision than the original data allows.

Complete step by step answer:
There are three rules on determining how many significant figures are in a number:
1. Non-zero digits are always significant.
2. Any zeros between two significant digits are significant.
3. A final zero or trailing zeros in the decimal portion ONLY are significant.

For multiplication and division use the following rule:
1.The LEAST number of significant figures in any number of the problem determines the number of significant figures in the answer. This means you have to be able to recognize significant figures in order to use this rule.Example: 5.26 has 3 significant figures, and 6.1 has 2 significant figures.
The number of significant figures in the question can be calculated by taking out the average of 25.20, 25.25 and 25.0, which is obtained as 25.1 .
In case of division, the final answer will contain as many significant figures as there are in a number with least significant numbers.
So, the significant number is 3.
So, the correct answer is “Option A”.

Note: For addition and subtraction use the following rules:
1. Count the number of significant figures in the decimal portion ONLY of each number in the problem
2. Add or subtract in the normal fashion
3. Your final answer may have no more significant figures to the right of the decimal than the LEAST number of significant figures in any number in the problem.