1.2g of carbon is burnt completely in oxygen (limted supply) to produce CO and `CO_(2)` . This mixture of gases is treated with solid `I_(2)O_(5)` (to know the amount of CO produced). The librated iodine required 120 ml of 0.1m hypo solution for complete titration. The percentage carbon converted into CO is :

Options

A. 0.6
B. 1
C. 0.5
D. 0.3

Answer

D

Explanation

`{:(,C,+,O_(2),rarr,CO,+,CO_(2)," "....(i)),(t=0,0.1,,,,-,,-,),(t=t,0,,,,x,,(0.1-x),),(,5CO,+,I_(2)O_(5),rarr,5CO_(2),+,I_(2),....(ii)),(t=0,x,,,,,,,),(t=t,0,,,,,,x//5,),(,,,,,,,,):}`
`I_(2)+2Na_(2)S_(2)O_(3)rarrNa_(2)S_(4)O_(6)+2"NaI"`
`:. ` moles of `I_(2)` liberated `=(1)/(2)xx`moles (from of hypo consumed `=(1)/(2)xx120xx10^(-3)xx0.1=60xx10^(-4)`
So, x `=5xx60xx10^(-4)=0.03` moles (from reaction (ii) `: 5 xx` mole of `I_(2)`=mole of CO)
so, % of C forming CO `=(0.03xx12)/(1.2)xx100=30%`