Question

What is the $pH$ of $N{a_2}C{O_3}$, sodium carbonate?

Answer 1

$pH$ denoting 'potential of hydrogen' or 'power of hydrogen' is a scale used to specify the acidity or basicity of an aqueous solution. Acidic solutions (solutions with higher concentrations of ${H^ + }$ ions) are measured to have lower $pH$ values than basic or alkaline solutions. At $25^\circ C$, solutions with a $pH$ less than $7$ are acidic, and solutions with a $pH$ greater than $7$ are basic.

Complete answer:
The $pH$ of sodium carbonate in water is close to $11$. The $pH$ is influenced by several factors in which concentration is an important one. Therefore, the $pH$ of sodium carbonate changes with the level of concentration of it in water. At $25^\circ C$, the change in $pH$ for different concentrations can be observed as follows:
-The $pH$ of $1wt\%$ sodium carbonate solution is $11.37$.
-The $pH$ of $5wt\%$ sodium carbonate solution is $11.58$.
-The $pH$ of $10wt\%$ sodium carbonate solution is $11.70$.
Instead of using the weight percentage we can use the mass of sodium carbonate added in water. Thus, for $1wt\%$, we can write $1g$ of sodium carbonate in water and so on.
Hence, we can say that the value of $pH$ keeps increasing with increased concentration of the solution.

Note:
The sodium carbonate solution is an aqueous solution and aqueous solutions are strongly alkaline. The $pH$ scale is logarithmic and inversely indicates the concentration of hydrogen ions in the solution. This is because the formula used to calculate $pH$ approximates the negative of the base $10$ logarithm of the molar concentration of hydrogen ions in the solution. More precisely, $pH$ is the negative of the base 10 logarithm of the activity of the ${H^ + }$ ion.