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Rate of Reaction

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Rate of Reaction

by mgmt_gmat » Thu Feb 11, 2010 5:27 am
43) The rate of a reaction is directly proportional to the square of the concentration of A and inversely proportional to concentration of B. If B increases by 100%, which of the following is closest to the % change in concentration of A required to keep the rate unchanged?
a. 100% decrease
b. 50% decrease
c. 40% decrease
d. 40% increase
e. 50% increase

Please explain.
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by ajith » Thu Feb 11, 2010 6:06 am
mgmt_gmat wrote:43) The rate of a reaction is directly proportional to the square of the concentration of A and inversely proportional to concentration of B. If B increases by 100%, which of the following is closest to the % change in concentration of A required to keep the rate unchanged?
a. 100% decrease
b. 50% decrease
c. 40% decrease
d. 40% increase
e. 50% increase

Please explain.
Rate of reaction r= k*x^2/y [ k - constant, x conc of A , y conc of B)
now if y becomes 2y for the rate to remain constant x^2 should become 2x^2
the x should become sqrt(2)*x or 1.41x => a 40% increase
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