Chemistry (Part-XII)

Total Questions: 50

31. Which gas is used by chemical leaveners, such as baking powder and baking soda, to lighten and aerate baked goods? [S.S.C. Online CPO SI (T-I) 09.11.2022 (Shift-I) ]

Correct Answer: (b) Carbon dioxide
Solution:Chemical leaveners, such as baking powder and baking soda, typically use carbon dioxide gas to lighten and aerate baked goods. When these leaveners are added to a recipe, they react with other ingredients, such as acid or moisture, to produce carbon dioxide gas. This gas forms bubbles in the batter or dough, which causes the mixture to expand and rise during baking, resulting in a lighter and fluffier texture.

32. What is the dominant chemical present in detergent powder? [S.S.C. Online Graduate Level (T-I) 12.06.2019 (Shift-I) ]

Correct Answer: (b) Sodium Carbonate
Solution:Sodium carbonate (Na₂CO₃) is found in detergent powder. Sodium carbonate is also called washing soda. Sodium carbonate is also used prominently in the manufacture of glass.

33. What is the chemical name of quicklime? [S.S.C. Online C.P.O.S.I. (T-I) 7.07.2017 (Shift-I) ]

Correct Answer: (b) calcium oxide
Solution:The chemical name of quicklime is calcium oxide and its chemical formula is CaO. It is also known as 'Burnt Lime'. It is a flammable, alkaline and crystalline solid substance of white colour.

34. Chemical formula of quick lime is ______ . [S.S.C. Online CGL (T-I) 01.12.2022 (Shift-I) ]

Correct Answer: (a) CaO
Solution:A chemical with the formula CaO, commonly called quick lime or hot lime. When hydrated with one mole of water, it forms slaked lime, Ca(OH)₂. Quick lime is preferred to slake lime at oil mud mixing plants because it generates heat when it becomes slaked with water and therefore speeds up emulsification by the reaction to form calcium fatty-acid soap.

35. What is obtained on adding quick lime to H₂O? [S.S.C. Online MTS (T-I) 3.10.2017 (Shift-II) ]

Correct Answer: (c) Slaked lime
Solution:When quicklime (calcium oxide, CaO) reacts with water (), it forms calcium hydroxide (). This reaction is highly exothermic (releases a lot of heat) and the product, calcium hydroxide, is commonly known as slaked lime.
The reaction is: .

36. Slaked lime is chemically known as: [S.S.C. JE Mechanical Exam 27.10.2020 (Shift-I) ]

Correct Answer: (a) Calcium hydroxide
Solution:Calcium oxide (CaO) i.e. also called quick lime, reacts with water (H₂O) to convert to calcium hydroxide [Ca(OH)₂]. Calcium hydroxide is also called slaked lime.

37. What is the chemical name of chalk? [S.S.C. Online Constable GD 22.02.2019 (Shift-I) ]

Correct Answer: (b) Calcium carbonate
Solution:Chalk is a chemical compound made up of calcium, carbon, and oxygen. The chemical name of chalk is calcium carbonate (CaCO₃).

38. Limestone, chalk and marble are different forms of ______ . [S.S.C. Online CGL (T-I) 02.12.2022 (Shift-II) ]

Correct Answer: (d) Calcium carbonate
Solution:Limestone, chalk and marble are different forms of calcium carbonate (CaCO₃).

Calcium phosphate is basic salt, as it is a salt of a weak acid (phosphoric acid) and a slightly stronger base (calcium hydroxide).

Limewater, also called milk of lime, is the com-mon name for a saturated solution of calcium hydroxide.

Quicklime is also called lime (calcium oxide (CaO)).

39. What is the chemical name of the deadly poison 'cyanide'? [S.S.C. Online Graduate Level (T-I) 12.06.2019 (Shift-II) ]

Correct Answer: (d) Prussic Acid
Solution:While "cyanide" refers to a group of chemical compounds containing a cyano group (), when referring to the deadly poison often discussed historically or in common parlance, it's typically hydrogen cyanide (HCN), which is also known as prussic acid. It's a highly volatile and toxic liquid or gas.

40. Limestone is a sedimentary rock, mainly composed of _____ . [S.S.C. Online Graduate Level (T-I) 19.06.2019 (Shift-III) ]

Correct Answer: (c) Calcium carbonate
Solution:Limestone is a sedimentary rock composed principally of Calcium Carbonate (Calcite) or the double carbonate of Calcium and Magnesium (dolomite).