JEE MainChemistrySome Basic Concepts of Chemistry
The molarity and molality of an aqueous solution of NaOH are 4 ~M and 4 ~m respectively. The density of the solution is :
Options
- A1.00 ~g/mL
- B0.84 ~g/mL
- C2.60 ~g/mL
- D1.16 ~g/mL
Correct answer
D. 1.16 ~g/mL
Step-by-step solution
We know the relation between molarity ( M ), molality ( m ), and density ( d in g/mL ) : m = 1000 M 1000 d - M M_w where M_w is the molar mass of the solute. For NaOH , the molar mass M_w = 40 ~g/mol . Substituting the given values ( M = 4 ~M and m = 4 ~m ) : 4 = 1000 4 1000 d - 4 40 1000 d - 160 = 1000 1000 d = 1160 d = 1.16 ~g/mL Answer: 1.16 ~g/mL