✓ 3 MARKS
Numericals
🔥 APPEARED IN 3 BOARD SETS
A first-order reaction is 25% complete in 40 minutes. Calculate the value of rate constant. In what time will the reaction be 80% complete ? [Given : $\log 2 = 0\cdot30$, $\log 3 = 0\cdot48$, $\log 4 = 0\cdot60$, $\log 5 = 0\cdot69$]
01 // VERIFIED BOARD OCCURRENCES
| Year | Paper Code | Set | Position |
|---|---|---|---|
| CBSE 2024 | Series 56-3 | Set 1 | Question 24 |
| CBSE 2024 | Series 56-3 | Set 2 | Question 25 |
| CBSE 2024 | Series 56-3 | Set 3 | Question 23 |
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)