Question

A certain reaction A + B $\longrightarrow$C, the first order with respect to each reactant k = 10–3. Determine the final concentration of A after 100 s, if the initial concentration of A was 0.1 M and that of B was 0.2 M.

• A. 0.098 M
• B. 0.088 M
• C. 0.078 M
• D. 0.068 M

Answer 1

Answer: (A)

0.098 M

Answer 2

$A + B \ \overset{\quad\quad}{\rightarrow}\ C$ $$\text{t = 0} \text{a = 0.1 M} \text{b = 0.2 M} 0 $$ $\text{t = 100s} \text{a - x} \text{b - x} x$From question , r = k[A][B] and hence

$$$$

or

}{\therefore \ \lbrack A\rbrack\text{ = 0.1 - x = 0.098 M }}$$