UKSSSC Forest SI (Forester) Exam Paper 11 June 2023 (Answer Key)

41. How many structural isomers can be formed by butane (C₄H₁₀)?
(A) 1
(B) 2
(C) 3
(D) 4

42. What is the unit of density?
(A) mole/litre
(B) kg m^-3
(C) gram cm^-3
(D) both (B) and (C)

43. Which of the following molecular compounds represents a correct chemical formula?
(A) Calcium chloride – CaCl
(B) Hydrogen sulphide – H₂S
(C) Sodium sulphate – NaSO₄
(D) Sodium sulphide – NaS

44. What is the chemical formula of Plaster of Paris?
(A) CaSO₄
(B) CaSO₄.½H₂O
(C) CaSO₄. 2H₂O
(D) Ca(OH)₂

45. How many number of moles are present in 128 g of SO₂?
(A) 01
(B) 02
(C) 03
(D) 04

46. Name the gas present in cooking gas cylinders in home.
(A) Compressed Natural Gas
(B) Liquified Petroleum Gas
(C) Liquified Hydrogen Gas
(D) Liquified Carbon dioxide Gas

47. The atomic radius decreases on moving from left to right along a period
(A) Due to increase in nuclear charge
(B) Due to decrease in nuclear charge
(C) Due to decrease in atomic number
(D) Due to increase in atomic number

48. Which of the following is used as anode in the electrolytic refining?
(A) Pure metal
(B) Impure metal
(C) Non-metal
(D) Metalloids

49. The isotope of which of the following element is used in the treatment of cancer?
(A) Iodine
(B) Uranium
(C) Cobalt
(D) Zinc

50. The given reaction is an example of
NaHCO₃ + HCl ⟶ NaCl + H₂O + CO₂
(A) Simple displacement
(B) Neutralisation
(C) Decomposition
(D) None of the above

51. Which of the following is acidic in nature?
(A) Antacid
(B) Lemon juices
(C) Human blood
(D) Milk of magnesia

52. The general formula for alkene is
(A) C_nH_2n
(B) C_nH_{2n + 2}
(C) C_nH_n
(D) C_nH_{2n – 2}

53. Evaporation increases with
i. Increase in surface area
ii. Increase in temperature
iii. Decrease in humidity
iv. Increase in wind speed
Choose the correct option from the following:
(A) i, ii, iii and iv
(B) Only ii
(C) Only iii
(D) Only iv

54. The chemical formula of bleaching powder is
(A) Ca(OH)₂
(B) CaCl₂
(C) CaCO₃
(D) CaOCl₂

55. Identify the oxidised and reduced substance in the following reaction:
CuO + H₂ → Cu + H₂O
(A) CuO is oxidised and H₂ is reduced
(B) CuO is reduced and H₂ is oxidised
(C) Only CuO is oxidised
(D) Only H₂ is reduced

56. Find the ratio of mass of combining elements in water (H₂O).
(A) 1:8
(B) 8:1
(C) 1:1
(D) 2:1

57. Arrange the following elements in the decreasing order of their metallic character:
Na, Si, Cl, Mg, Al
(A) Na > Mg > Al > Si > Cl
(B) Al> Na > Mg > Si > Cl
(C) Mg> Na > Al > Si > Cl
(D) Si > Na > Mg > Al > Cl

58. Propane, with the molecular formula, C₃H₈ has
(A) 11 covalent bonds
(B) 10 covalent bonds
(C) 12 covalent bonds
(D) 09 covalent bonds

59. The atomicity of sulphur is
(A) Monoatomic
(B) Diatomic
(C) Tetraatomic
(D) Polyatomic

60. Buckminster fullerene is an allotropic form of
(A) Phosphorus
(B) Sulphur
(C) Carbon
(D) Tin