Organic Acids (Organic Chemistry)

Total Questions: 29

11. Which one of the following pairs is not correctly matched? [U.P.P.C.S. (Mains) 2015]

Correct Answer: (c) Acetic acid - Curd
Solution:Ascorbic acid or vitamin C is found in many fresh vegetables and fruits such as cauliflower, lemon, cabbage, and citrus fruits. Maltose is found in malt. Malt is a germinated cereal that has been dried in a process known as "Malting". Lactic acid is found in curd, not acetic acid. Formic acid occurs in the body of red ants and in the stings of bees.

12. Table: Match List-I with List-II and select the correct answer using the codes given below the lists: [U.P.P.C.S. (Mains) 2003]

List-IList-II
A. Pickle1. Carbonic Acid
B. Sour Milk2. Acetic Acid
C. Apple3. Lactic Acid
D. Cold drinks and soda water4. Malic Acid

Code:

 

CodeABCD
(a)1342
(b)2341
(c)3412
(d)4231
Correct Answer: (b)
Solution:The correctly matched lists are as follows:
  • Pickle → Acetic Acid
  • Sour Milk → Lactic Acid
  • Apple → Malic Acid
  • Cold Drinks and Soda Water → Carbonic Acid

13. Which of the following is NOT correctly matched? [U.P.P.C.S. (Pre) 2021]

Correct Answer: (c) Souring of milk – Nitric acid
Solution:Soured milk denotes a range of food products produced by the acidification of milk. It is the lactic acid which makes the milk sour. Pairs of other options are correctly matched.

14. Milk openly placed for some time becomes sour due to – [U.P. Lower Sub. (Pre) 2004]

Correct Answer: (b) Lactic acid
Solution:Milk contains a sugar called lactose. It also contains harmless bacteria called lactobacillus, which uses glucose for energy and creates lactic acid as a by-product. It is the lactic acid which makes the milk sour. The presence of lactic acid or lactate in milk is due to the fermentation of lactose caused mainly by lactic bacteria.

15. Which one of the following acids is present in sour milk products? [U.P.P.C.S. (Mains) 2012]

Correct Answer: (d) Lactic acid
Solution:Milk contains a sugar called lactose. It also contains harmless bacteria called lactobacillus, which uses glucose for energy and creates lactic acid as a by-product. It is the lactic acid which makes the milk sour. The presence of lactic acid or lactate in milk is due to the fermentation of lactose caused mainly by lactic bacteria.

16. Which one of the following acids is formed during the change of milk into curd? [R.A.S./R.T.S. (Pre) 2008]

Correct Answer: (d) Lactic acid
Solution:When pasteurized milk is heated to a temperature of 30-40°C or even at room temperature and a small amount of old curd or whey is added to it, the lactobacillus (bacteria) in that curd or whey sample starts to grow. They convert the lactose into lactic acid, which imparts the sour taste to curd.

17. Curd making is an ancient "Biotechnological" process involving – [R.A.S./R.T.S. (Pre) 2010]

Correct Answer: (a) Bacteria
Solution:When pasteurized milk is heated to a temperature of 30-40°C or even at room temperature and a small amount of old curd or whey is added to it, the lactobacillus (bacteria) in that curd or whey sample starts to grow. They convert the lactose into lactic acid, which imparts the sour taste to curd.

18. The predominant organic acid in grapes is – [U.P.P.C.S. (Spl.) (Mains) 2008]

Correct Answer: (d) Tartaric acid
Solution:Tartaric acid is the predominant organic acid in grapes. It is a white crystalline diprotic acid.

19. For human nutrition, tomatoes are a rich source of – [R.A.S./R.T.S. (Re. Exam) (Pre) 2013]

Correct Answer: (c) Citric acid
Solution:Tomato contains mainly citric acid and malic acid. Due to which, it also acts as an antacid. It also contains oxalic acid which is found less in quantity.

20. Which one of the following organic acids is abundant in grapes, tamarind, and banana? [U.P.P.C.S(Pre)2017]

Correct Answer: (d) Tartaric acid
Solution:Tartaric acid is found in abundance in grapes, tamarind, and banana. This acid is used as a regulator and antioxidant in food items.