Biomolecules · JEE Main previous year questions

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2020 10 questions

Q712020 · 3 Sept 2020 · Shift 1· Numerical answer
The mole fraction of glucose ( $C_{6} H_{12} O_{6}$ ) in an aqueous binary solution is 0.1. The mass percentage of water in it, to the nearest integer, is _______.
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Answer: 47
Q732020 · 3 Sept 2020 · Shift 2· Numerical answer
If $250 c m^{3}$ of an aqueous solution containing $0.73 g$ of a protein A is isotonic with one litre of another aqueous solution containing $1.65 g$ of a protein B, at $298 K$ , the ratio of the molecular masses of A and B is ____ $\times 1 0^{- 2}$ (to the nearest integer).
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Answer: 177
Q752020 · 3 Sept 2020 · Shift 2· Numerical answer
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Answer: 5
Q562020 · 2 Sept 2020 · Shift 1
An open beaker of water in equilibrium with water vapour is in a sealed container. When a few grams of glucose are added to the beaker of water, the rate at which water molecules :
1. A.leaves the solution increases
2. B.leaves the vapour increases
3. C.leaves the vapour decreases
4. D.leaves the solution decreases
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Answer: D
Q572020 · 2 Sept 2020 · Shift 1
Consider the following reactions: (i) $Glucose + ROH dry HCl Acetal x eq. of (C H_{3} CO)_{2} O acetyl derivative$ (ii) $Glucose Ni/ H_{2} A y eq. of (C H_{3} CO)_{2} O acetyl derivative$ (iii) $Glucose z eq. of (C H_{3} CO)_{2} O acetyl derivative$ 'x', 'y' and 'z' in these reactions are respectively.
1. A.5, 6 & 5
2. B.4, 5 & 5
3. C.4, 6 & 5
4. D.5, 4 & 5
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Answer: C
Q742020 · 2 Sept 2020 · Shift 1· Numerical answer
The internal energy change (in J) When $90 g$ of water undergoes complete evaporation at $10 0^{\circ} C$ is ____. (Given : $Δ H_{vap}$ for water at $373 K = 41 kJ/mol$ , $R = 8.314 J K^{- 1} mo l^{- 1}$ )
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Answer: 189494 to 189495
Q642020 · 8 Jan 2020 · Shift 1
Which of the following statement is not true for glucose?
1. A.Glucose gives Schiff's test for aldehyde
2. B.Glucose reacts with hydroxylamine to form oxime
3. C.The pentaacetate of glucose does not react with hydroxylamine to give oxime
4. D.Glucose exists in two crystalline forms $α$ and $β$
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Answer: A
Q622020 · 8 Jan 2020 · Shift 2
Two monomers in maltose are :
1. A. $α$ -D-glucose and $α$ -D-galactose
2. B. $α$ -D-glucose and $α$ -D-Fructose
3. C. $α$ -D-glucose and $α$ -D-glucose
4. D. $α$ -D-glucose and $β$ -D-glucose
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Answer: C
Q662020 · 8 Jan 2020 · Shift 2
Among the reactions (a) - (d), the reaction(s) that does/do not occur in the blast furnace during the extraction of iron is/are : (a) $CaO + Si O_{2} \to CaSi O_{3}$ (b) $3F e_{2} O_{3} + CO \to 2F e_{3} O_{4} + C O_{2}$ (c) $FeO + Si O_{2} \to FeSi O_{3}$ (d) $FeO \to Fe + \frac{1}{2} O_{2}$
1. A.(a) and (d)
2. B.(c) and (d)
3. C.(a)
4. D.(d)
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Answer: B
Q722020 · 8 Jan 2020 · Shift 2· Numerical answer
At constant volume, 4 mol of an ideal gas when heated from 300 K to 500K changes its internal energy by 5000 J. The molar heat capacity at constant volume is _______.
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Answer: 6.25