Verified Solution • 2025–26 Session moderate

QJEEM21Chd271: JEE Main 2021 Chemistry - Class 12 JEEM21Chd271 Solution: The inactivation rate of a viral preparation is proportional to …

The inactivation rate of a viral preparation is proportional to the amount of virus. In the first minute after preparation, 10% of the virus is inactivated. The rate constant for viral inactivation is ___________ ×\times 10 −- 3 min −- 1. (Nearest integer)

[Use : ln 10 = 2.303; log10 3 = 0.477; property
of logarithm : log xy = y log x]

Step-by-Step Verified Solution

Unit of rate constant is min −- 1, so it must be a first order reaction. For first order reaction,

k ×\times t = 2.303 log A0At{{{A_0}} \over {{A_t}}}

k is the rate constant

t is the time

A0 is the initial conc.

At is the conc. at time, t

Using formula,

A0 = 100, At = 90 min 1 min

So, K ×\times 1 = 2.303 ×\times log 10090{{100} \over {90}}

= 2.303 ×\times (log 10 −- 2 log 3)

= 2.303 ×\times (1 −- 2 ×\times 0.477)

= 0.10593

= 105.93 ×\times 10 −- 3

≈\approx 106

Hence, the rate constant for viral inactivation is 106.

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