Question

What is the \[pH\] of a \[0.050\;M\] \[NaOH\]solutioin \[?\]

Answer 1

Hint: First, we need to know the properties and characteristics of the given compound. Then we have to know what is \[pH\] using this. How can we say that a given compound is acidic or base or neutral. Then find the \[pH\] value of the given compound.

Complete answer:
\[NaOH\] is the chemical formula of sodium hydroxide. It is also known as Caustic soda.
Properties of Caustic soda: It is a white solid which has a melting point of \[591K\]. It is a stable compound. NaOH is bitter and has a soapy feel to it. It is highly soluble in water and moderately soluble in alcohol. Sodium hydroxide is strongly alkaline in nature.
Caustic soda is used as a cleansing agent and in the manufacturing of washing soda. Sometimes, sodium hydroxide is also used as a reagent in the laboratories. It is used in the preparation of soda lime. It is used in the extraction of aluminium by purifying bauxite.
\[pH\] is a measure of how acidic/basic water is. The range goes from \[0\] to \[14\], with \[7\] being neutral. \[pH\] of less than \[7\] indicates acidity, whereas a \[pH\] of greater than \[7\] indicates a base. \[pH\] is really a measure of the relative amount of free hydrogen and hydroxyl ions in the water.
Since, we know that \[NaOH\] is a strong base, meaning it will dissociate basically completely in solution to form \[N{a^ + }\] and \[O{H^ - }\] ions in solution.
One mole of \[O{H^ - }\] ions are created for every mole of NaOH that is dissolved. If it's a \[0.05M\] solution of \[NaOH\], then it can also be interpreted to be a \[0.05M\] solution of \[O{H^ - }\].
\[pOH\] (The pH scale for bases) can be found by taking the negative logarithm of \[O{H^ - }\] concentration.
\[pOH = - \log \left[ {0.05M} \right] = 1.3\]
However, we are trying to find \[pH\], so we must use the formula
\[pOH + pH = 14\]
Substituting the value of \[pOH\]in the above equation, we get
\[pH = 14 - 1.3 = 2.7\].

Note:
Note that Caustic soda is an alkali salt which is also called Lye. It is the common name of sodium hydroxide. This name is given due to the corrosive nature of this salt on animal and plant tissues.