A gaseous reaction `A_(2)(g) rarr B(g) + (1)/(2) C(g)` shows increase in pressure form `100 mm` to `120 mm` in `5 min`. What is the rate of disappearance of `A_(2)` ?

Options

A. `4 "mm min"^(-1)`
B. `8 "mm min"^(-1)`
C. `16 "mm min"^(-1)`
D. `2 "mm min"^(-1)`

Answer

B

Explanation

`{:(A_(2)(g)rarrB(g)+(1)/(2)C(g)),("P - -"),("P-p p p/2"):}`
Increase in pressure `=(p)/(2)`
Thus, the increase of pressure refers to the increase in concentration if C
Rate of apperance of C `=(120-100)/(5)`
= 4 mm `"min"^(-1)`
Rate of disapperance of `A_(2)=2xx"rate of appearance of C"=2xx"4 mm min"^(-1)="8 mm min"^(-1)`