Question

Question 1.19 How many significant figures are present in the following?

(i) 0.0025

(ii) 208

(iii) 5005

(iv) 126,000

(v) 500.0

(vi) 2.0034

Class XI Some Basic Concepts of Chemistry Page 23

Answer 1

concept :
1. all non - zero digits are significant .
2. zeros present to left /right of a number are non - significant however zero present after decimal points are significant .
3. zeros present between two non - zero digits are significant .


(i) 0.0025
according to rule 2 , there are 2 significant figure in 0.0025.

(ii) 208
according to rule 1 and 3 , there are 3 significant figures in 208.

(iii)5005
according to rule 1 and 3, there are 4 significant figures in 5005.

(iv) 126000
according to rule 2,there are 3 significant figures in 126000.

(v) 500.0
according to rule 2 , there are 4 significant figures in 500.0

(vi) 2.0034
according to rule 2, there are 5 significant figures in 2.0034

Answer 2

(i) 0.0025= 2 significant figure

(ii) 208= 3 S.F.

(iii) 5005= 4 S.F

(iv) 126,000= 3 S.F

(v) 500.0= 4 S.F

(vi) 2.0034= 5 S.F