1. The component balance of the component A is given as
a) FzF= DxD + Wxw
b) FzF= DxD – Wxw
c) FzF= DxD/Wxw
d) FzF= DxD *Wxw
Explanation: According to McCabe Thiele method material balance over is given as FzF= DxD + Wxw, where F is the total feed.
2. If F= 200 kmol/h and ZF=0.4, XD=0.95, XW=0.04 and R=2.0, Then D is
a) 88.1
b) 22.6
c) 79.1
d) 158.2
Explanation: Using equation FzF= DxD + Wxw substituting values we get D=79.1.
3. The very First step of McCabe method is?
a) Plot the equilibrium curve
b) Plot diagonal curve
c) Plot Operating line
d) Plot stripping line
Explanation: Firstly we plot the Equilibrium diagram from the given equilibrium data, then the diagonal curve and then plot the operating line.
4. Calculate Boil up? If vapor flow and bottom withdrawal are 237.3 and 120.9 respectively
a) 1.5
b) 2.9
c) 2.111
d) 1.963
Explanation: As boil up is ratio of vapor flow and bottom withdrawal then 237.3/120.9 = 1.963.
5. If ZF¬=0.58 and also feed contains 35% mole of the liquid, then intercept of y axis is
a) 0.892
b) 0.205
c) 0.707
d) Can’t be calculated
Explanation: As – (ZF/q-1) using values -0.58/ (0.35-1) = 0.892
6. If ZF=0.6 and also feed contains 72% mole of the liquid, then intercept of x axis is
a) 0.744
b) 0.899
c) 0.833
d) 1.2
Explanation: As (ZF/q) using values 0.6/ (0.72) = 0.833.
7. Calculate minimum reflux? If intercept is 0.56 and XD= 0.96
a) 0.174
b) 0.125
c) 0.21
d) 0.28
Explanation: As 0.56=XD/ (RM+1) = 0.96/ (RM+1) M= 0.174.
8. Slope of rectifying line is given by
a) R/XD
b) R/(R+1)
c) F/ (D+W)
d) R/(R+1)
Explanation: The rectifying line slope is always given as ratio of Reflux ratio plus unity i.e. R/(R+1), While R/XD gives us the reflux to liquid ratio for the operation.
9. If xD=0.95, xW= 0.04 and α=2.5. Find total trays?
a) 7
b) 6.7
c) 7.7
d) 6
Explanation: Using Fenske’s equation total number of trays to be calculate are 5.7 as Nm + 1 then 5.7+1 = 6.7 which is the final answer.
10. A Pinch point may occur at intersection of feed line and
a) Stream line
b) Stripping line
c) Rectifying line
d) Equilibrium line
Explanation: Pinch point always occurs at intersection of feed line and equilibrium line, while plot of x and y are called as the Equilibrium line.