Discussion
3.0 g of a salt of molecular weight 30 is dissolved in 250 mL of water. The molarity of the solution is
Answer: D
The molarity is 0.4 M.
Molarity is moles of solute per litre of solution (taking the solution volume as 250 mL).
\[ \begin{aligned} n &= \frac{3.0}{30} = 0.1\ \text{mol} \\ M &= \frac{0.1}{0.25} = 0.4\ \text{M} \end{aligned} \]
0.1 M forgets to divide by the volume in litres, and 0.3 M or 0.5 M come from using the wrong volume. Molarity uses litres of solution, while molality would use kilograms of solvent; with 250 mL of water both give about 0.4 here.
No comment is present. Be the first to comment.
Loading…
Post your comment
Please log in or register to post a comment.
Examination Categories
- SSC Exams
- Banking Exams
- Teaching Exams
- Civil Services Exams
- Railways Exams
- Engineering Recruitment Exams
- Defence Exams
- State Government Exams
- Police Exams
- Insurance Exams
- Nursing Exams
- Other Government Exams
- NRA CET
- PG Entrance Exams
- Campus Placement
- MBA Entrance Exams
- CUET and UG Entrance
- Judiciary Exams
- Regulatory Body Exams
- Software Development