This set of Engineering Chemistry Multiple Choice Questions & Answers (MCQs) focuses on “Characteristics of Electroplating Wastes”.
1. Under what condition will impurities form under cathode?
a) When temperature exceeds critical temperature
b) When pressure exceeds critical pressure
c) When the amount of electrolyte is increased enormously
d) When water content is increased
Explanation: Since during electroplating, the standard critical temperature and pressure are maintained. If the temperature is increased, then only the polarities of the electrode change, but if the pressure is increased, the impurities will shift from anode to cathode.
2. Which of the following is not the characteristic of impurities in electroplating?
a) Are formed near cathode
b) Are mostly noble metals
c) Are formed near anode
d) Increase the strength of solution
Explanation: During electroplating, the impurities are mostly noble metals (especially in the case of alkali and alkaline earth metals). That is why due to higher density at anode, the impurities are formed near anode.
3. What causes an increase in the amount of formation of impurities at a higher rate?
a) Increase in concentration
b) Decrease in concentration
c) Deterioration in the amount of molecules
d) Destruction in the electrode
Explanation: During electroplating process, the amount of molecules plays an important role in the determination of electrolysis of absorbent (water or any other fluid). Thus decrease in the amount of molecules will increase the formation of impurities.
4. Determine the coefficient of relative constant from the following data.
Alpha = 23
C = 43 g
T = 100 K
Explanation: We know that the relative constant can be calculated from the formula: C/T X alpha. Therefore from the given data, we can calculate the constant as 43/100×23 = 9.89.
5. Determine the coefficient of the relative constant from the following data.
Alpha = 1
C = 3 g
T = 10 K
Explanation: We know that the relative constant can be calculated from the formula: C/T X alpha. Therefore from the given data, we can calculate the constant as 3/100×1=0.3.
6. What will be the observation when the electrolyte concentration is increased to double times the previous concentration?
a) The Composition increases 4 times
b) The composition increases 2 times
c) The composition increases 8 times
d) The composition does not change
Explanation: Since during electroplating the concentration of the electrolyte is independent of external factors like temperature of the system, pressure and specific gravity, it does not have anything to do with composition.
7. Determine the curational capacity of zinc aluminium from the following.
a) Noblular transmission
b) Isotropic mass activation
c) Semi concentric circulation
d) Isobaric transmission
Explanation: During electroplating process, the contents like concentration, composition, electronic configuration of molecules are purely based on the ingenious capacity of electrolysis process, the curational capacity is isotropic in nature.
8. Calculate the electron concentration.
C = 3
T = 23 K
Explanation: We know that the electron concentration is given by the formula concentration/alpha value. Therefore in this problem, from the given data, we have the value of electron concentration as 34/3=11.3.
9. Calculate the value of alpha from the following.
Electron concentration: 4
Explanation: We know that the electron concentration is given by the formula concentration/alpha value. Therefore alpha = electron concentration x C. Therefore in this problem, from the given data, we have the value of alpha as 4×2=8.
10. The emulsified impurities are found near ____________
d) At electrolyte site
Explanation: Since during the process of electroplating, the higher density molecules adhere to the anode and lower density molecules adhere to cathode. Since emulsified impurities are low density molecules, they stick towards cathode.
Sanfoundry Global Education & Learning Series – Engineering Chemistry.
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