Hydrogen & s-Block · JEE Main previous year questions

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2020 9 questions

Q682020 · 6 Sept 2020 · Shift 1
Among the sulphates of alkaline earth metals, the solubilities of $BeS O_{4}$ and $MgS O_{4}$ in water, respectively, are :
1. A.poor and poor
2. B.poor and high
3. C.high and poor
4. D.high and high
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Answer: D
Q642020 · 6 Sept 2020 · Shift 2
Match the following compounds (Column-I) with their uses (Column-II) : | S.No. | Column-I | S.No. | Column-II | | :--- | :--- | :--- | :--- | | (I) | $Ca (OH)_{2}$ | (A) | casts of statues | | (II) | $NaCl$ | (B) | white wash | | (III) | $CaS O_{4} \cdot \frac{1}{2} H_{2} O$ | (C) | antacid | | (IV) | $CaC O_{3}$ | (D) | washing soda preparation |
1. A.(I)-(B), (II)-(C), (III)-(D), (IV)-(A)
2. B.(I)-(B), (II)-(D), (III)-(A), (IV)-(C)
3. C.(I)-(C), (II)-(D), (III)-(B), (IV)-(A)
4. D.(I)-(D), (II)-(A), (III)-(C), (IV)-(B)
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Answer: B
Q642020 · 3 Sept 2020 · Shift 2
1. A.(b) only
2. B.(b) and (d)
3. C.(c) and (d)
4. D.(d) only
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Answer: A
Q682020 · 9 Jan 2020 · Shift 1
A chemist has 4 samples of artificial sweetener A, B, C and D. To identify these samples, he performed certain experiments and noted the following observations : (i) A and D both form blue-violet colour with ninhydrin. (ii) Lassaigne extract of C gives positive $AgN O_{3}$ test and negative $F e_{4} [Fe (CN)_{6}]_{3}$ test. (iii) Lassaigne extract of B and D gives positive sodium nitroprusside test Based on these observations which option is correct ?
1. A.A : Aspartame ; B : Alitame ; C : Saccharin ; D : Sucralose
2. B.A : Alitame ; B : Saccharin ; C : Aspartame ; D : Sucralose
3. C.A : Aspartame ; B : Saccharin ; C : Sucralose ; D : Alitame
4. D.A : Saccharin ; B : Alitame ; C : Sucralose ; D : Aspartame
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Answer: C
Q592020 · 9 Jan 2020 · Shift 2
5 g of zinc is treated separately with an excess of (a) dilute hydrochloric acid and (b) aqueous sodium hydroxide. The ratio of the volumes of $H_{2}$ evolved in these two reactions is :
1. A.1 : 2
2. B.1 : 1
3. C.1 : 4
4. D.2 : 1
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Answer: B
Q692020 · 9 Jan 2020 · Shift 2
Among the statements (a)-(d) the correct ones are : (a) Lithium has the highest hydration enthalpy among the alkali metals. (b) Lithium chloride is insoluble in pyridine. (c) Lithium cannot form ethynide upon its reaction with ethyne. (d) Both lithium and magnesium react slowly with $H_{2} O$ .
1. A.(b) and (c) only
2. B.(a) and (d) only
3. C.(a), (b) and (d) only
4. D.(a), (c) and (d) only
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Answer: D
Q682020 · 8 Jan 2020 · Shift 1
When gypsum is heated to 393 K, it forms :
1. A. $CaS O_{4} \cdot 0.5 H_{2} O$
2. B. $CaS O_{4} \cdot 5 H_{2} O$
3. C.Dead burnt plaster
4. D.Anhydrous $CaS O_{4}$
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Answer: A
Q632020 · 7 Jan 2020 · Shift 2
The ammonia ( $N H_{3}$ ) released on quantitative reaction of 0.6 g urea ( $N H_{2} CON H_{2}$ ) with sodium hydroxide ( $NaOH$ ) can be neutralized by :
1. A.200 ml of 0.02 N HCl
2. B.100 ml of 0.2 N HCl
3. C.100 ml of 0.1 N HCl
4. D.200 ml of 0.4 N HCl
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Answer: B
Q702020 · 7 Jan 2020 · Shift 2
Among the statements (a) - (d), the correct ones are : (a) Decomposition of hydrogen peroxide gives dioxygen. (b) Like hydrogen peroxide, compounds, such as $KCl O_{3}$ , $Pb (N O_{3})_{2}$ and $NaN O_{3}$ when heated liberate dioxygen. (c) 2-Ethylanthraquinone is useful for the industrial preparation of hydrogen peroxide. (d) Hydrogen peroxide is used for the manufacture of sodium perborate.
1. A.(a), (b), (c) and (d)
2. B.(a) and (c) only
3. C.(a), (b) and (c) only
4. D.(a), (c) and (d) only
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Answer: A