A flask contains a mixture of compounds A and B. Both compounds d… - Vidyadip

MCQ

A flask contains a mixture of compounds $A$ and $B.$ Both compounds decompose by first-order kinetics. The half-lives for $A$ and $B$ are $300$ $s$ and $180\, s ,$ respectively. If the concentrations of $A$ and $B$ are equal initially, the time required for the concentration of $A$ to be four times that of $B ($ in $s ):$ (Use $\ln 2=0.693)$

A
$180$
B
$120$
C
$300$
✓
$900$

✓

Answer

Correct option: D.

$900$

d
$[ A ]_{ t }=4[ B ]_{ t }$

$[ A ]_{0} e ^{-\left( in ^{2} / 300\right)^{t}}=4[ B ]_{0} e ^{(-\ln 2 / 180) t }$

$e^{\left(\frac{in^{2}}{180}-\frac{in^{2}}{300}\right)}=4$

$\left(\frac{\ln ^{2}}{180}-\frac{\ln ^{2}}{300}\right) t =\ln 4$

$\left(\frac{1}{180}-\frac{1}{300}\right) t=2 \Rightarrow t=\frac{2 \times 180 \times 300}{120}=900 sec$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

NEET STD 11 Science question papers→Gujarat Board STD 11 Science question papers→Gujarat Board question paper generator→

Similar questions

Boiling Ethylamine on reaction with acidified $KMnO_4$ gives :

In any ferric salt, on adding potassium ferrocyanide, a prussian blue colour is obtained, which is

A certain quantity of electricity is passed through an aqueous solution of $AgN{O_3}$ and cupric salt solution connected in series. The amount of $Ag$ deposited is $1.08\,gm$, the amount of copper deposited is ............. $\mathrm{g}$ (atomic weight of $Cu = 63.5$ ; $Ag = 108$)

Which of the following exhibit maximum oxidation state of vanadium

Which of the following statements are correct for an electron that has $n = 4$ and $m = -2$ ?

The right option for the mass of $CO _2$ produced by heating $20 g$ of $20 \%$ pure limestone is $........\,g$(Atomic mass of $Ca =40$ )$\left[ CaCO _3 \stackrel{1200 K }{\longrightarrow} CaO + CO _2\right]$

In the combustion of hydrocarbons, $\Delta H$ is

Select the hybrdisation which have non planar geometry when all are bond pair, but planar when there are $2$ lone pairs on central atom :

Which one of the following is true about $NaCl$ and $KCl$

Which of the following compounds is not colored yellow ?