✓ Board-verified
Chemistry · 2022 · 3 marks
CBSE 2022 · Region 2 · Set 1 · Q7
A first order reduction takes 30 minutes for 75% decomposition. Calculate t_1 / 2. Given: [ log 2=0 · 3, log 3=0 · 48, log 4=0 · 6, log 5=0 · 7]
A first order reduction takes $\displaystyle 30$ minutes for $\displaystyle 75$% decomposition. Calculate $\displaystyle \mathrm{t}_{1 / 2}$. Given : $\displaystyle [\log 2=0 \cdot 3, \quad \log 3=0 \cdot 48, \quad \log 4=0 \cdot 6, \quad \log 5=0 \cdot 7]$
Marking-scheme solution
\[k=\frac{2 \cdot 303}{t} \log \frac{(R)_{0}}{(R)}
\]
\[k=\frac{2 \cdot 303}{30} \log \frac{100}{25}
\]
\[k=\frac{2 \cdot 303}{30} \log 4=0 \cdot 046 \mathrm{~min}^{-1}
\]
\[t_{1 / 2}=\frac{0 \cdot 693}{k}=\frac{0 \cdot 693}{0 \cdot 046}
\]
\[t_{1 / 2}=15 \mathrm{~min}
\]
All Chemical Kinetics questions2022 question paperNCERT solutions: Chemical KineticsPractice Chemical Kinetics →
More from Chemical Kinetics
- Assertion: Order of reaction is applicable to elementary as well as complex reactions. Reason (R): For a complex reaction molecularity has no meaning.2023 · asked 2×
- For the reaction 3 A → 2 B, rate of reaction +(d[B])/dt is equal to2023 · asked 2×
- Assertion: For a zero order reaction the unit of rate constant and rate of reaction are same. Reason (R): Rate of reaction for zero order reaction is…2023 · asked 2×
- Assertion: Hydrolysis of an ester follows first order kinetics. Reason (R): The concentration of water does not get altered much during the reaction.2025
- Show that the time required for 99.9 % completion in a first order reaction is 10 times of half-life (t_1 / 2) of the reaction [ log 2=0.3010, log…2024
- In the given reaction N_2( g)+3 H_2( g) → 2 NH_3( g) the rate of formation of NH_3 is 3 · 6 × 10^-4 mol L^-1 s^-1. Calculate the (i) rate of…2022
- Reactant 'A' underwent a decomposition reaction. The concentration of 'A' was measured periodically and recorded in the table given below: Based on…2025
- Which of the following curve represents the first order reaction?2026
CBSE Class 12 Chemistry past-paper question from the 2022 board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.