Question

The correct order of $pH$ is
a.) \[~Lemon\text{ }juice < water < Milk\text{ }of\text{ }magnesia\]
b.) \[~Lemon\text{ }juice > water > Milk\text{ }of\text{ }magnesia\]
c.) \[~water > Lemon\text{ }juice > Milk\text{ }of\text{ }magnesia\]
d.) \[~Milk\text{ }of\text{ }magnesia~ > Lemon\text{ }juice > water\]

Answer 1

Hint: $pH$ of a solution is generally defined as the negative logarithm (base 10) of the Hydrogen concentration and is generally used to conveniently express relative acidity or alkalinity of a solution.
- $pH$ Units decrease with increasing acidity by a factor of 10.


Complete Solution :
To find the appropriate solution and option of the given question, we need to primarily get briefed on $pH$ of all the solutions mentioned in the options.
- Lemon juice in its natural state is acidic with its $pH$ of about $2$ but once it is metabolized it actually becomes alkaline with a $pH$ well above $7$ .
- $pH$ is generally a measure of acidity or alkalinity and as per the water quality regulations specify, the $pH$ of tap water should be between $6.5$ and $9.5$.
- Milk of Magnesia is a medication that is used for a short time to treat occasional constipation and might act as a laxative. The $pH$ of milk of magnesia is about $10.5$.
Conclusively, Milk of Magnesia is basic, water is neutral and lemon juice is acidic in nature.
So, the correct answer is “Option A”.

Note: One is advised to remember that if the concentration of ${{H}_{3}}{{O}^{+}}$ ion in pure water at ${{25}^{\circ }}C$ is $1.0\times {{10}^{-7}}M$ , the $pH$ of pure water is $7$, when the $pH$ of a solution is less than $7$, the solution is acidic and when the $pH$ is more than $7$, the solution is basic.