This set of Applied Chemistry Interview Questions and Answers for Experienced people focuses on “Saponification Value – 2”.
1. The saponification value is given by ______
a) Saponification value = (volume of KOH +NKOH+56)/wt of the oil taken
b) Saponification value = (volume of KOH * NKOH/56)/wt of the oil taken
c) Saponification value = (volume of KOH * NKOH*56)/wt of the oil taken
d) Saponification value = (volume of KOH – NKOH-56)/wt of the oil taken
Explanation: The saponification value is given by Saponification value = (volume of KOH * NKOH*56)/wt of the oil taken. So, to determine the saponification value first we need to know the volume of KOH utilised.
2. What is the acid value of the groundnut oil?
Explanation: The acid value of the groundnut oil is 0.2-8.0. Castor oil has the acid value of 0.4-0.8. Coconut oil is having a high acid value that is about 10.0-35.2.
3. What is the saponification oil of coconut oil?
Explanation: The saponification value of the coconut oil is very high because it has very high acid value. The saponification value of the coconut is 253-203. The more acid value is the high the saponification value.
4. Which of the following has no acid value?
a) Cotton seed oil
b) Rape seed oil
c) Whale oil
d) Hard oil
Explanation: Hard oil has no acid value. Cotton seed oil has the acid value of 194-195. Rape seed oil has low acid value that is about 1.4-4.0. The whale oil has the acidic value of 0.3-51.4.
5. The saponification value of the hard oil is _________
Explanation: The saponification value of the hard oil is 192-198. Though it has no acid value it has saponification value. 194-195 is the saponification value of the cotton seed oil. Groundnut oil and whale oil has the saponification values of 194-196 and 190-191 respectively.
6. The percentage of fatty oil when compounded in the oil is given by _________
Explanation: The percentage of fatty oil when compounded in the oil is given by (C/F)*100. Here, C = saponification value of the compounded or lubricating oil and F = saponification of the fatty oil.
7. Triglyceride reacts with glycerol to form _________
a) Sodium of fatty acid
b) Potassium of fatty acid
c) Magnesium of fatty acid
d) Chlorides of fatty acids
Explanation: Triglyceride reacts with glycerol to produce the potassium of fatty acids. The potassium of fatty acids are called as soaps. Mainly alkyl groups of triglycerides and glycerol are made to react.
8. In determination of saponification value of the oil reaction _______ is unreacted.
Explanation: In determination of the saponification value of the oil reaction, KOH is unreacted. The KOH is used as the catalyst and it remains unreacted and then titrated with standard acid using phenolphthalein as an indicator.
9. Find the acid value of the vegetable oil whose 10ml required 4.0ml of 0.01N KOH during titration (d = 0.92).
Explanation: To find out the acid value of an oil we know the formula, acid value= (volume of KOH*N KOH*56)/wt of the oil in mg. Wt of the oil can be known by calculating the product of density and volume to get 9.2gm. Substitute the values in formula to get 0.243mg as the answer.
10. The saponification value also indicates _______
a) Number of carbons
b) Number of alkyl groups
c) Number of fatty acids
d) Length of the carbon chain
Explanation: The saponification value also indicates the length of the carbon chain in the particular oil or fat. Higher the saponification value greater the percentage of the short chain acids present in glycerides.
Sanfoundry Global Education & Learning Series – Applied Chemistry.
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