✓ 3 MARKS
Reasoning / Why
🔥 APPEARED IN 3 BOARD SETS
(a) Shweta mixed two liquids A and B of $10\text{ mL}$ each. After mixing, the volume of the solution was found to be $20\cdot2\text{ mL}$.
(i) Why was there a volume change after mixing the liquids ?
(ii) Will there be an increase or decrease of temperature after mixing ?
(iii) Give one example for this type of solution.
OR
(b) (i) How does sprinkling of salt help in clearing the snow covered roads in hilly areas ?
(ii) What happens when red blood cells are kept in $0\cdot5% \text{ (mass/vol)}$ $\text{NaCl}$ solution ? Justify your answer.
(iii) Write an application of reverse osmosis.
01 // VERIFIED BOARD OCCURRENCES
| Year | Paper Code | Set | Position |
|---|---|---|---|
| CBSE 2025 | Series 56-5 | Set 1 | Question 22 |
| CBSE 2025 | Series 56-5 | Set 2 | Question 23 |
| CBSE 2025 | Series 56-5 | Set 3 | Question 22 |
02 // OFFICIAL CBSE MARKING SCHEME BREAKDOWN
- Step 1: Stating the fundamental formula / law statement (+1 Mark)
- Step 2: Intermediate mathematical substitution or proof steps (+1 Mark)
- Step 3: Correct final value or conclusion with mandatory SI units (+1 Mark)