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.

$(a)$ Neutral $\rightarrow$ Solution $D$ with $pH\, 7$

$(b)$ Strongly alkaline $\rightarrow$ Solution $C$ with $pH\, 11$

$(c)$ Strongly acidic $\rightarrow$ Solution $B$ with $pH \,1$

$(d)$ Weakly acidic $\rightarrow$ Solution $A$ with $pH \,4$

$(e)$ Weakly alkaline $\rightarrow$ Solution $E$ with $pH \,9$

The $pH$ can be arranged in the increasing order of the concentration of hydrogen ions as:

$11 < 9 < 7 < 4 < 1$