List of practice Questions

A spherical naphthalene ball of 2 mm diameter is subliming very slowly in stagnant air at 25°(C) The change in the size of the ball during the sublimation can be neglecte(D) The diffusivity of naphthalene in air at 25°C is \(1.1 \times 10^{-6} \, m^2/s\). The value of mass transfer coefficient is \( B \times 10^{-3} \, m/s \), where \( B \) (up to one decimal place) is —————.

A mixture of toluene (40%) and benzene (60%) is fed to the distillation column; recovery of benzene is 20% at the top. What is the ratio of the flow rate of benzene from Distillate to the bottoms? (Based on 1000 Kg of feed)?

In a triple-effect backward feed evaporator, the pressure of vapor space in each of the effects is related by —————.
(Hint: Use steam entry as the first effect) 

Kirkbride equation is used for determining the —————.
Which of the following happens in the use of Raschig rings in place of crushed stones as packing in packed beds (other things being same)?
A chemical having specific heat of 3.3 kJ/kg K flowing at the rate of 20000 kg/h enters a parallel flow heat exchanger at 120°(C) The flow rate of cooling water is 50000 kg/h with an inlet temperature of 20°(C) The overall heat transfer coefficient is 1050 W/m\(^2\)K. The heat transfer area is 10 m\(^2\). Take for water, specific heat = 4.186 kJ/kgK. Effectiveness of the heat exchanger will be —————.
The Sun’s surface at 5800 K emits radiation at a wavelength of 0.5 \(\mu m\). A furnace at 300°C will emit through a small opening, radiation at a wavelength of nearly —————.
In a furnace, the wall thickness is 60 cm and is 100 cm wide by 150 cm height, made of material with thermal conductivity 0.4 W/mK. The temperature inside and outside are 1000°C and 4°C, respectively. The thermal resistance is —————.

In a completely opaque medium, if 50 percent of the incident monochromatic radiation is absorbed, which of the following statements are CORRECT? 
- (P) 50 percent of the incident radiation is reflected 
- (Q) 25 percent of the incident radiation is reflected 
- (R) 25 percent of the incident radiation is transmitted 
- (S) No incident radiation is transmitted

For true counter-current flow in a shell and tube heat exchanger, the value of correction factor \( F_T \) is —————.
What is the Knudsen diffusion coefficient for cumene at 510°C through the pores of a catalyst of porosity 0.51 and density 1.14 g/cm³? The specific surface area is 342 m²/g.
Catalyst pellets have a density of 2.0 g/c(C) If the specific surface area is 75 m²/g and the average pore diameter is \( 8 \times 10^{-7} \) cm, what is the porosity of the catalyst?
A reaction \( A \to B \) is to be conducted in two CSTRs in series. The steady-state conversion desired is \( X_f \). The reaction rate as a function of conversion is given by \( r = -\frac{1}{1 + X} \). If the feed contains no B, then the conversion in the first reactor that minimizes the total volume of the two reactors is

What mass of 75% pure CaCO3 will be required to neutralize 50 ml of 0.5M HCL solution according to the following reaction? \[ {CaCO}_3 + 2{HCl} \to {CaCl}_2 + {CO}_2 + {H}_2{O} \]

What is the Knudsen diffusion coefficient for cumene at 510°C through the pores of a catalyst of porosity 0.51 and density 1.14 g/cm³? The specific surface area is 342 m²/g.
Catalyst pellets have a density of 2.0 g/c(C) If the specific surface area is 75 m²/g and the average pore diameter is \( 8 \times 10^{-7} \) cm, what is the porosity of the catalyst?
A reaction \( A \to B \) is to be conducted in two CSTRs in series. The steady-state conversion desired is \( X_f \). The reaction rate as a function of conversion is given by \( r = -\frac{1}{1 + X} \). If the feed contains no B, then the conversion in the first reactor that minimizes the total volume of the two reactors is

A gaseous reaction \( A \to 2B + C \) takes place isothermally in a constant pressure reactor. Starting with a gaseous mixture containing 50% A (rest inerts), the ratio of final to initial volume is found to be 1.6. The percentage conversion of A is

Assuming that CO2 obeys the perfect gas law, the density of CO2 in kg/m\(^3\) at 536 K and 202.6 kPa is
The change in the Gibbs free energy for the vaporization of a pure substance is

In the process of producing caustic (NaOH), 4000 kg/h of a solution containing 10 wt% NaOH is evaporated in the first evaporator, giving a 20% NaOH solution. This is then fed into a second evaporator which gives a product of 50% NaOH. The amount of water removed from each evaporator is

What is the heat capacity of Na2SO4.10H2O at room temperature using Kopp’s rule?

What mass of 75% pure CaCO3 will be required to neutralize 50 ml of 0.5M HCL solution according to the following reaction? \[ {CaCO}_3 + 2{HCl} \to {CaCl}_2 + {CO}_2 + {H}_2{O} \]

CaCO3 contains ________ of Calcium. 
 

What is the temperature at which °C is equal to °F?