Problem Solving Strategy

Question 1
Marks : +2 | -2
Pass Ratio : 100%
Solution-1 containing 40% acetic acid and 20% carbon dioxide at the rate F combines with Solution-2 containing 20% acetic acid and 40% carbon dioxide at the rate D, the product formed contains 30% acetic acid at the rate P, what is the percentage of carbon dioxide in product?
10%
20%
30%
40%
Explanation:
The equations for material balance are: 0.4F + 0.2D = 0.3P, F + D = P, and 0.2F + 0.4D = yP, solving these we get y = 0.3, => percentage of carbon dioxide = 30%.
Question 2
Marks : +2 | -2
Pass Ratio : 100%
Solution-1 at the rate F combines with solution-2 at the rate D, their combination gives the product at the rate P, what is the equation of material balance?
F + D = P
F – P = D
D – F = P
None of the mentioned
Explanation:
The general equation of material balance is F + D = P.
Question 3
Marks : +2 | -2
Pass Ratio : 100%
Solution-1 containing 20% w1 and w2 at the rate 10 Kg/min combines with Solution-2 containing 10% w1, 20% w2 and w3 at the rate 20 Kg/min, the product formed contains and 10% w1, 30% w2 and 20% w3, what is the percentage of w2 in solution-1?
5%
10%
25%
50%
Explanation:
Rate of product, P = 10 + 20 = 30 Kg/min, equation of material balance for w2: x(10) + 0.2(20) = 0.3(30), => w2 = 0.5, => percentage of w2 = 50%.
Question 4
Marks : +2 | -2
Pass Ratio : 100%
Solution-1 containing 10% nitric acid and 20% acetic acid at the rate F combines with Solution-2 containing 20% nitric acid and 10% acetic acid at the rate D, the product formed contains 30% nitric acid and 20% acetic acid at the rate P, how many independent equations containing F, D, and P are possible?
1
2
3
4
Explanation:
The equations of material balance are: 0.1F + 0.2D = 0.3P, 0.2F + 0.1D = 0.2P, and F + D = P.
Question 5
Marks : +2 | -2
Pass Ratio : 100%
Solution-1 containing 10% nitric acid flowing at the rate 10 Kg/min combines with Solution-2 containing 40% nitric acid flowing at the rate 5 Kg/min, if their product contains 30% nitric acid, what is the flow rate of product?
10 Kg/min
20 Kg/min
30 Kg/min
40 Kg/min
Explanation:
Equation of material balance, 0.1(10) + 0.4(5) = 0.3(x), => x = 10 Kg/min.
Question 6
Marks : +2 | -2
Pass Ratio : 100%
Solution-1 containing 40% nitric acid and 20% carbon dioxide at the rate F combines with Solution-2 containing 30% nitric acid and 40% carbon dioxide at the rate D, the product formed contains 30% nitric acid and 20% carbon dioxide at the rate P, If P = xF what is x?
1
2
3
4
Explanation:
The equations of material balance are: 0.4F + 0.2D = 0.3P, 0.2F + 0.4D = 0.3P, and F + D = P, Solving these we get D = F = P/2, => x = 2.
Question 7
Marks : +2 | -2
Pass Ratio : 100%
CH4 at the rate 10 mole/min is reacted with O2 at the rate 10 mole/min, what is the rate of formation of CO2 in the product?
5 mole/min
10 mole/min
20 mole/min
40 mole/min
Explanation:
The balanced chemical reaction is: CH4 + 2O2 -> CO2 + 2H2O, this means O2 is the limiting reagent, => rate of formation of CO2 = 10/2 = 5 mole/min.
Question 8
Marks : +2 | -2
Pass Ratio : 100%
Solution-1 containing 10% hydrochloric acid and 20% acetic acid at the rate F combines with Solution-2 containing 20% hydrochloric acid and 30% acetic acid at the rate D, the product formed contains 20% hydrochloric acid and 30% acetic acid at the rate P, how many independent equations containing F, D, and P are possible?
1
2
3
4
Explanation:
The equations of material balance are: 0.1F + 0.2D = 0.2P, 0.2F + 0.3D = 0.3P and F + D = P, but if we subtract first two of them then we get the third, so number of independent equations are 2.
Question 9
Marks : +2 | -2
Pass Ratio : 100%
Solution-1 containing 30% sulfuric acid flowing at the rate 10 Kg/min combines with Solution-2 containing 20% sulfuric acid flowing at the rate 5 Kg/min, if their product is out at the rate 20 Kg/min what is the percentage of sulfuric acid in the product?
10%
20%
30%
40%
Explanation:
Equation of material balance, 0.3(10) + 0.2(5) = x(20), => x = 0.2, => Percentage of sulfuric acid in the product = 20%.
Question 10
Marks : +2 | -2
Pass Ratio : 100%
CH4 at the rate 10 mole/min is reacted with O2 at the rate 30 mole/min, what is the rate of formation of CO2 in the product?
5 mole/min
10 mole/min
20 mole/min
40 mole/min
Explanation:
The balanced chemical reaction is: CH4 + 2O2 -> CO2 + 2H2O, this means CH4 is the limiting reagent, => rate of formation of CO2 = 10 mole/min.