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प्रश्न
Define half life of a reaction.
उत्तर
Half life of a reaction is defined as the time required for the reactant concentration to reach one half of its initial value.
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संबंधित प्रश्न
The integrated rate equation for first order reaction is A → products
Derive the relation between half life and rate constant for a first order reaction
The experimental data for decomposition of N2O5
\[\ce{2N2O5 -> 4NO2 + O2}\] in gas phase at 318K are given below:
| t/s | 0 | 400 | 800 | 1200 | 1600 | 2000 | 2400 | 2800 | 3200 |
| 102 × [N2O5]/mol L−1 | 1.63 | 1.36 | 1.14 | 0.93 | 0.78 | 0.64 | 0.53 | 0.43 | 0.35 |
- Plot [N2O5] against t.
- Find the half-life period for the reaction.
- Draw a graph between log [N2O5] and t.
- What is the rate law?
- Calculate the rate constant.
- Calculate the half-life period from k and compare it with (ii).
The rate constant for the first order decomposition of H2O2 is given by the following equation:
log k = 14.34 − 1.25 × 104 K/T. Calculate Ea for this reaction and at what temperature will its half-period be 256 minutes?
Which among the following reactions is an example of a zero order reaction?
a) `H_(2(g)) + I_(2(g)) -> 2HI_(g)`
b) `2H_2O_(2(l)) -> 2H_2O_(l) + O_(2(g))`
c) `C_12H_22O_(11(aq)) + H_2O_(l) -> C_6H_12O_(6(aq)) + C_6H_12O_(6(aq))`
d) `2NH_(3g)` `N(2g) + 3H_(2(g))`
The half life period of a radioactive element is 140 days. After 560 days, 1 g of element will be reduced to
Calculate half-life period of life order reaction whose rate constant is 200 sec–1
Show that the half-life of zero order reaction is `t_(1/2) = ([A]_0)/(2k)`.
Calculate the half-life of a first order reaction from the rate constant given below:
2 min−1
A first order reaction takes 40 min for 30% decomposition. Calculate `"t"_(1/2)`.
