✓ 3 MARKS
Numericals
🔥 APPEARED IN 3 BOARD SETS
For the first order thermal decomposition reaction, following data was obtained :
$\text{C}_2\text{H}_5\text{Cl(g)} \longrightarrow \text{C}_2\text{H}_4\text{(g)} + \text{HCl(g)}$
| S. No. | Time(s) | Total Pressure (atm) |
| :---: | :---: | :---: |
| 1 | 0 | 0.30 |
| 2 | 30 | 0.50 |
Calculate rate constant. $\quad \quad \quad \quad \quad \quad \quad \quad \quad \quad \quad \quad \quad$ [Given : $\log 3 = 0.48$]
01 // VERIFIED BOARD OCCURRENCES
| Year | Paper Code | Set | Position |
|---|---|---|---|
| CBSE 2026 | Series 56-1 | Set 1 | Question 22 |
| CBSE 2026 | Series 56-1 | Set 2 | Question 26 |
| CBSE 2026 | Series 56-1 | Set 3 | Question 25 |
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)