✓ 2 MARKS
Numericals
🔥 APPEARED IN 3 BOARD SETS
A
The concentration of the reactant is reduced from $0.6 \text{ mol L}^{-1}$ to $0.2 \text{ mol L}^{-1}$ in 5 minutes in a first order reaction. Calculate rate constant of the reaction. $(\log 3 = 0.48)$
OR
B
Rate constant $k$ for the first order reaction is $2.54 \times 10^{-3} \text{ s}^{-1}$. Calculate the time required for three-fourth of the reactant to decompose.
$(\log 4 = 0.60)$
01 // VERIFIED BOARD OCCURRENCES
| Year | Paper Code | Set | Position |
|---|---|---|---|
| CBSE 2026 | Series 56-2 | Set 1 | Question 17 |
| CBSE 2026 | Series 56-2 | Set 2 | Question 21 |
| CBSE 2026 | Series 56-2 | Set 3 | Question 20 |
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)