Chemistry (Part-XI)

41. Sour taste of lemon is due to the presence of which of the following? [S.S.C. Online Graduate Level (T-I) 8.09.2016 (Shift-II) ]

(a) Citric acid
(b) Acetic acid
(c) Oxalic acid
(d) Formic acid

Correct Answer: (a) Citric acid

Solution:Lemons, like other citrus fruits (oranges, limes, grapefruits), are rich in citric acid. This organic acid is responsible for their characteristic sour and tart taste.

42. In which of the following options is the substance INCORRECTLY paired with the acid present in that substance? [S.S.C. Online C.H.S.L. (T-I) 09.08.2021 (Shift-II) ]

(a) Lemon - Lactic Acid
(b) Orange - Citric Acid
(c) Vinegar - Acetic Acid
(d) Tomato - Oxalic Acid

Correct Answer: (a) Lemon - Lactic Acid

Solution:The sourness found in lemon is due to the citric acid present in it. Lactic acid is responsible for the conversion of milk into curd. Other options are correctly matched.

43. In which of the following is citric acid present? [S.S.C. Online Graduate Level (T-I) 9.03.2020 (Shift-I) ]

(a) Curd
(b) Lemon
(c) Tamarind
(d) Black Gram

Correct Answer: (b) Lemon

Solution:The sourness found in lemon is due to the citric acid present in it. Lactic acid is responsible for the conversion of milk into curd.

44. Which of the following acid is present in sour milk? [S.S.C. Online MTS (T-I) 21.09.2017 (Shift-II) ]

(a) Formic acid
(b) Lactic acid
(c) Citric Acid
(d) Tartaric Acid

Correct Answer: (b) Lactic acid

Solution:When milk sours, it's due to the fermentation of lactose (milk sugar) by bacteria (like Lactobacillus). This process produces lactic acid, which gives sour milk, yogurt, and other fermented dairy products their characteristic tangy taste.

45. Which of the following acids is NOT present in grapes? [S.S.C. Online Graduate Level (T-I) 5.03.2020 (Shift-III) ]

(a) Tartaric acid
(b) Acetic acid
(c) Citric acid
(d) Malic acid

Correct Answer: (b) Acetic acid

Solution:Different types of organic acids are found in grapes, such as malic acid, tartaric acid, and citric acid, etc. But acetic acid is not found in grapes. Acetic acid is found in vinegar.

46. Which of the following acids found in Apple? [S.S.C. Online Graduate Level (T-I) 6.06.2019 (Shift-III) ]

(a) Malic Acid
(b) Sulphuric Acid
(c) Formic Acid
(d) Nitric Acid

Correct Answer: (a) Malic Acid

Solution:Malic acid is the predominant acid found in apples, giving them their tart and sometimes slightly sour taste. The name "malic" comes from the Latin word "malum," meaning apple.

47. Which of the following acid-source pairs is correctly matched? [S.S.C. Online MTS (T-I) 14.08.2019 (Shift-III) ]

(a) Citric Acid - Lemon
(b) Lactic Acid - Vinegar
(c) Formic Acid - Tamarind
(d) Acetic Acid - Ant's sting

Correct Answer: (a) Citric Acid - Lemon

Solution:The correct matching is:

List-I	List-II
Citric acid	lemon
Lactic acid	milk
Formic acid	ant sting
Acetic acid	vinegar

Tartaric acid is found in tamarind.

48. Which acid is present in tomatoes? [S.S.C. Online Constable GD 22.02.2019 (Shift-II) ]

(a) Tartaric acid
(b) Sulfenic acid
(c) Malic Acid
(d) Oxalic acid

Correct Answer: (d) Oxalic acid

Solution:Citric acid is mainly found in tomatoes and oxalic acid is found in moderate amounts in tomatoes. In fact, as tomatoes ripen, the amount of vitamin C (ascorbic acid) decreases, while the amount of oxalic acid increases.

49. Name the acid present in tamarind. [S.S.C. Online Constable GD 18.02.2019 (Shift-III) ]

(a) Lactic acid
(b) Tartaric acid
(c) Citric acid
(d) Amino acids

Correct Answer: (b) Tartaric acid

Solution:Tartaric acid is prominent among the acids found in tamarind, due to which excessive sourness is found in tamarind.

50. What is the product formed when sodium bicarbonate is heated strongly? [S.S.C. Online Graduate Level (T-I) 29.08.2016 (Shift-I) ]

(a) Sodium Carbonate
(b) Sodium Hydroxide
(c) Sodium Peroxide
(d) Sodium Monoxide

Correct Answer: (a) Sodium Carbonate

Solution:When sodium bicarbonate (NaHCO₃, baking soda) is heated strongly, it undergoes thermal decomposition to produce sodium carbonate (Na₂CO₃), carbon dioxide gas (CO₂), and water (H₂O). This reaction is commonly used in baking, where the released CO₂ causes dough to rise.

2NaHCO₃ → Na₂CO₃ + H₂O + CO₂