10cm3 of CO is mixed and sparked with 100cm3 of air containing 21% O2. If all the volumes measured at S.T.P. the volume of resulting gases would be?
A
90cm3
B
100cm3
C
105cm3
D
110cm3
E
115cm3
Verified Correct Answer: C.
Chemical Principles & Mechanism
2CO(g) + O2(g) ---> 2CO\(_2\)(g)
2vol 1vol 2vol
Volume in cm\(^3\) Before sparking: 10 // 21
Volume in cm\(^3\) On sparking 10 // 5 // 10
Volume in cm\(^3\) After sparking: 0// 16 // 10
Total volume of resulting gas = Volume of [excess oxygen + CO\(_2\) produced + unreactive components]
= 16 + 10 + 79 → 105cm\(^3\)
Source: WAEC / JAMB / NECO Classroom Archive (Record #12779)