Question

Consider the reaction, $2A + B \to$ When concentration of $B$ alone was doubled, the half-life did not change. When the concentration of $A$ alone was doubled, the rate increased by two times. The unit of rate constant for this reaction is

• A. $L \,mol^{-1}\, s^{-1}$
• B. no unit
• C. $mol^{-1}\, s^{-1}$
• D. $s^{-1}$

Answer 1

Answer: (A)

$2A+B \rightarrow $ Products
When conc. of B is doubled, the half life did not change, hence reaction is of first order w.r.t. B. When concentration of A is doubled, reaction rate is
Hence over all order of reaction is $1 + 1 = 2$
So, unit of rate constant $mol^{-1}\, lit\, s^{-1}.$
Hence, (1) is correct.