53. The maximum permissible limit for fluoride in drinking water is

(A) 0.1 mg/litre (B) 1.5 mg/litre
(C) 5 mgi/litre (D) 10 mg/litre
54. What is the working pH range for methyl orange ?
(A) 64-0 (8) 12-8 (6) 3.1-4 (0) 60-8

55. Which of the following are least soluble forms of Ca and Mg at Normal water
temperature ?

(A) CaCl, and MgCO, ൯ Ca(HCO,), and MgCl,
(C) Ca(OH), and Mg(HCO,), @) CaCO, and Mg(OH),
56. A water sample has a pH of 9.25. The concentration of hydroxyl ions in the water sample 15
(^) 10-9.25 moles/L (8) 10-4.75 moles/L
(C) 0.302 mg/L (D) 3.020 mg/L
57. The process in which the chlorination is done beyond the break point is known as
(^) Pre-chlorination (8) Post-chlorination
(C) Super chlorination (2) Break point chlorination
58. Match the given water properties in Group-I to the given titrants shown in Group-II
Group-I Group-II
2. | Alkalinity 1. |N/35.5 AgNO,
(९. | Hardness 2. |N/40 Na,S,0,
R. |Chlorine 3. 1450 H,SO,
9. |Dissolved oxygen 4. |N/S0 EDTA

(^) 7-1, 0-2, ௩3, 4
(8) 7-2, 0-1, ௩4, 5-3
(൭ 7-3, 0-4, ‏برع‎ 5-2
(0) 7-4, 0-3, ௩2, $-1

59. Which of the following cations impart(s) pseudo-hardness to water ?

(^) Calcium only (B) Magnesium only
(C) Calcium and magnesium (D) Sodium
60. ൧ single rapid test to determine the pollution status of river water is
(A) Biochemical oxygen demand (B) Chemical oxygen demand
(C) Total organic solids (D) Dissolved oxygen

61. As per IS 1893 : 2002 “A soft storey is one in which the lateral stiffness is less than what
% of that in the storey above or less than 80 percent of the average lateral stiffness of the
three storeys above.

(A) 70 percent (B) 80 percent
(C) 75 percent (D) 90 percent

62. As per IS 13920 : 2016, what is the minimum grade of structural concrete that should be
used in buildings ?
(A) 30 (B) 25 (©) 15 (D) 20

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