Question

# What is the molecular weight of NaOH?

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Hint: Sodium hydroxide is a base, used in a number of reactions. The constituents of sodium hydroxide are sodium, oxygen and hydrogen. The molecular weight of any compound is the sum of the respective weight of atoms in that compound.

Complete answer: We have been given a compound NaOH, which is sodium hydroxide. We have to find its molecular weight.
The molecular weight of any compound is the sum of the atomic masses of all the atoms of the constituent elements of that compound.
Sodium hydroxide, NaOH, will possess the atomic weights of sodium, oxygen and hydrogen. The sum of the atomic weight of these elements will give us the molecular weight of sodium hydroxide, NaOH.
Now, molar weight of sodium, Na = 22.990 = 23 g/mol
Molar weight of oxygen, O = 15.999 = 16 g/mol
Molar weight of hydrogen, H = 1.008 = 1 g/mol
Now the molecular weight will be,
Molar weight of NaOH = mass of Na + mass of O + mass of H
Molar weight of NaOH = (23 + 16 + 1) g/mol
Molar weight of NaOH = 40 g/mol
Hence, the molecular weight of sodium hydroxide, NaOH is calculated to be 40 g per mole.

Note: The atomic mass of any element is written in gram per mole, because it is the mass of that element in 1 mole of the atoms of that element or we can say that in $6.022\times {{10}^{23}}$ particles of that element.