Question

. Five solutions A,B,C,D and E when tested with universal indicator showed pH as
4,1,11,7 and 9, respectively. Which solution is
(a) neutral?
(b) strongly alkaline?
(c) strongly acidic?
(d) weakly acidic?
(e) weakly alkaline?
Arrange the pH in increasing order of hydrogen-ion concentration.

NCERT Class 10th Science Chapter 2 Acids Bases and Salts

Answer 1

ph given 
a=4,b=1c=11,d=7 ,e =9
 dis the neutral
c is the stronger alkaline sol
b is strongly acidic
a is weakly acidic
e is weakely alkaline
increasing order
c,<e<d<a<b

Answer 2

(a) Neutral- pH 7.

(b) Strongly alkaline- pH 11.

(c) Strongly acidic- pH 1.

(d) Weakly acidic- pH 4.

(e) Weakly alkaline-pH 9.

• The neutral range has a pH value of 7. The acid lies in the pH range of below 7 and the bases lie in the pH range of above 7. As the pH value decreases acidity increases and as the pH value increases basicity increases.
• Hence we can write-
• (a) Neutral- pH 7.
• (b) Strongly alkaline- pH 11.
• (c) Strongly acidic- pH 1
• (d) Weakly acidic- pH 4.
• (e) Weakly alkaline-pH 9.
• Again as the pH value decreases the concentration of hydrogen ions increases. So, the pH can be arranged as follows in increasing order of hydrogen-ion concentration-
• C<E<D<A<B