This set of Basic Chemical Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Recycle with Chemical Reaction”.
1. In a reaction where the feed rate of component W is given as 50 mole/hr, what is the value of W?
a) 10 mole/hr
b) 40 mole/hr
c) 50 mole/hr
d) 90 mole/hr
View answer
Explanation: W = 10 + 40 = 50 mole/hr.
2. For a reaction where A converts to 2B, if component W flows at 50 mole/hr, what is the flow rate of product P in mole/hr?
a) 5 mole/hr
b) 10 mole/hr
c) 25 mole/hr
d) 40 mole/hr
View answer
Explanation: P = 20% of W, => P = 50*20/100 = 10 mole/hr.
3. In a reaction where A -> 2B and W = 50 mole/hr, what is the overall extent of reaction?
a) 5
b) 10
c) 20
d) 25
View answer
Explanation: Extent of reaction = (P – 0)/2 = (10 – 0)/2.
4. For the reaction A -> 2B, if W = 50 mole/hr, what is the overall fraction conversion of A?
a) 10%
b) 20%
c) 80%
d) 100%
View answer
Explanation: Overall fraction conversion = (10 – 0)/10*100 = 100%.
5. In the reaction A -> 2B with a feed rate W = 50 mole/hr, what is the single pass fraction conversion of A?
a) 10%
b) 20%
c) 25%
d) 50%
View answer
Explanation: Single pass fraction conversion = (50 – 40)/50*100 = 20%.
6. For the reaction C2H4 + H2 -> C2H6, with an overall conversion rate of C2H4 at 90% and a single-pass conversion rate of 20%, what is the extent of reaction?
a) 3.6
b) 4.8
c) 6.4
d) 7.2
View answer
Explanation: Extent of reaction = 4*0.9/1 = 3.6.
7. In the reaction C2H4 + H2 -> C2H6, if the extent of reaction is 3.6, how many moles of ethane (C2H6) are produced?
a) 2.4
b) 3.6
c) 6.4
d) 7.2
View answer
Explanation: Moles of C2H6 = 3.6*1 = 3.6.
8. For the reaction C2H4 + H2 -> C2H6, with an extent of reaction at 3.6, what is the product flow rate (P) in mole/hr?
a) 3.6 mole/hr
b) 5.4 mole/hr
c) 6.4 mole/hr
d) 7.8 mole/hr
View answer
Explanation: The extent of reaction = (4*0.9)/1 = 3.6, => moles of C2H6 = 3.6, moles of H2 = 6 – 3.6 = 2.4, moles of C2H4 = 4 – 3.6 = 0.4, => P = 3.6 + 2.4 + 0.4 = 6.4 moles/hr.
9. In a system where the reaction C2H4 + H2 -> C2H6 occurs with an extent of reaction at 3.6, what is the recycle rate (R) in mole/hr?
a) 18.4 mole/hr
b) 44 mole/hr
c) 70 mole/hr
d) 98.5 mole/hr
View answer
Explanation: 0.2 = – (-3.6)/(4 + 0.2*R), => R = 70 mole/hr.
10. For the reaction C2H4 + H2 -> C2H6, where the extent of reaction is 3.6 and the single pass conversion rate is 20%, what is the gas flow rate (G) in mole/hr?
a) 10 mole/hr
b) 30 mole/hr
c) 70 mole/hr
d) 80 mole/hr
View answer
Explanation: G = 10 + 70 = 80 mole/hr.
11. In the reaction C6H12 -> C6H6 + 3H2, if the extent of reaction is 16, what is the extent of reaction?
a) 4
b) 8
c) 12
d) 16
View answer
Explanation: Moles of C6H12 in feed = 80, => extent of reaction = (80*0.2 – 80)/(-1) = 64.
12. For the reaction C6H12 -> C6H6 + 3H2, with an extent of reaction of 16, how many moles of benzene (C6H6) are formed?
a) 8
b) 16
c) 32
d) 64
View answer
Explanation: Moles of benzene formed = 64*1 = 64.
13. In a system where the reaction C6H12 -> C6H6 + 3H2 has an extent of reaction of 16, what is the product flow rate (P) in mole/hr?
a) 64 mole/hr
b) 192 mole/hr
c) 272 mole/hr
d) 512 mole/hr
View answer
Explanation: Moles of benzene = 64, moles of hexane = 80 – 80*0.8 = 16, moles of H2 = 64*3 = 192, => P = 64 + 16 + 192 = 272 mole/hr.
14. For the reaction C6H12 -> C6H6 + 3H2, if the extent of reaction is 16 and the single pass conversion rate is 20%, what is the recycle rate (R) in mole/hr?
a) 600 mole/hr
b) 720 mole/hr
c) 880 mole/hr
d) 960 mole/hr
View answer
Explanation: 0.2 = – (-64)/(80 + 0.4*R), => R = 600 mole/hr.
15. In a system where the reaction C6H12 -> C6H6 + 3H2 occurs with an extent of reaction at 16, what is the gas flow rate (G) in mole/hr?
a) 600 mole/hr
b) 700 mole/hr
c) 800 mole/hr
d) 900 mole/hr
View answer
Explanation: G = 100 + 600 = 700 mole/hr.
Sanfoundry Global Education & Learning Series – Basic Chemical Engineering.
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