If 8g NaOH is dissolved in 1L of solution,its molarity is:-
Answers
As M = moles/volume
Therefore, 8÷40/1
1÷5 =. 0.2 M
Answer- The above question is from the chapter 'Some Basic Concepts of Chemistry'.
Molarity: Number of moles of solute present in 1 litre of solution is called molarity.
Unit of Molarity = Molar (M)
•Number of moles = Given mass/Gram atomic/molecular mass
•When volume is given in litres,
Molarity = No. of moles of solute ÷ Volume of solution in litres
•When volume is given in millilitres,
Molarity = (No. of moles of solute × 1000) ÷ Volume of solution in ml
Given question: If 8 g NaOH is dissolved in 1 L of solution, its molarity is:-
(Atomic masses of Na = 23, O = 16 and H = 1)
Solution: Given mass of NaOH = 8 g
Gram molecular mass of NaOH = 1[Na] + 1[O] + 1[H] = 23 + 16 + 1 = 40 g
Number of moles of NaOH = Given mass/Gram atomic/molecular mass
= 8/40 = 1/5 = 0.2 moles
Volume = 1 litre
Molarity = No. of moles of solute ÷ Volume of solution in litres
∴ Molarity = 0.2/1 = 02 Molar or 0.2 M