p-Block Elements · JEE Main previous year questions

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2022 41 questions

Q882022 · 29 Jul 2022 · Shift 1· Numerical answer
In bromination of Propyne, with Bromine, 1, 1, 2, 2-tetrabromopropane is obtained in 27% yield. The amount of 1, 1, 2, 2-tetrabromopropane obtained from $1 g$ of Bromine in this reaction is ________ $\times 1 0^{- 1} g$ . (Nearest integer) (Molar Mass : Bromine = 80 g/mol)
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Answer: 3
Q632022 · 29 Jul 2022 · Shift 2
$C (s) + O_{2} (g) \to C O_{2} (g) + 400 kJ$ $C (s) + \frac{1}{2} O_{2} (g) \to CO (g) + 100 kJ$ When coal of purity $60%$ is allowed to burn in presence of insufficient oxygen, $60%$ of carbon is converted into 'CO' and the remaining is converted into ' $C O_{2}$ '. The heat generated when $0.6 kg$ of coal is burnt is ____.
1. A. $1600 kJ$
2. B. $3200 kJ$
3. C. $4400 kJ$
4. D. $6600 kJ$
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Answer: D
Q782022 · 29 Jul 2022 · Shift 2
When borax is heated with $CoO$ on a platinum loop, blue coloured bead formed is largely due to :
1. A. $B_{2} O_{3}$
2. B. $Co (B O_{2})_{2}$
3. C. $Co B_{4} O_{7}$
4. D. $Co [B_{4} O_{5} (OH)_{4}]$
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Answer: B
Q792022 · 29 Jul 2022 · Shift 2
Dinitrogen is a robust compound, but reacts at high altitudes to form oxides. The oxide of nitrogen that can damage plant leaves and retard photosynthesis is :
1. A. $NO$
2. B. $N O_{3}^{-}$
3. C. $N O_{2}$
4. D. $N O_{2}^{-}$
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Answer: C
Q892022 · 29 Jul 2022 · Shift 2· Numerical answer
Consider the following sulphur based oxoacids. $H_{2} S O_{3}$ , $H_{2} S O_{4}$ , $H_{2} S_{2} O_{8}$ and $H_{2} S_{2} O_{7}$ . Amongst these oxoacids, the number of those with peroxo ( $O - O$ ) bond is ____.
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Answer: 1
Q902022 · 29 Jul 2022 · Shift 2· Numerical answer
The number of chlorine atoms in bithionol is __________.
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Answer: 4
Q862022 · 28 Jul 2022 · Shift 1· Numerical answer
The number of interhalogens from the following having square pyramidal structure is : $ClF_{3}$ , $IF_{7}$ , $BrF_{5}$ , $BrF_{3}$ , $I_{2} Cl_{6}$ , $IF_{5}$ , $ClF$ , $ClF_{5}$
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Answer: 3
Q892022 · 28 Jul 2022 · Shift 1· Numerical answer
On complete combustion of $0.492 g$ of an organic compound containing C, H and O, $0.7938 g$ of $CO_{2}$ and $0.4428 g$ of $H_{2} O$ was produced. The % composition of oxygen in the compound is _________.
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Answer: 46
Q662022 · 28 Jul 2022 · Shift 2
Dinitrogen and dioxygen, the main constituents of air do not react with each other in atmosphere to form oxides of nitrogen because :
1. A. $N_{2}$ is unreactive in the condition of atmosphere.
2. B.Oxides of nitrogen are unstable.
3. C.Reaction between them can occur in the presence of a catalyst.
4. D.The reaction is endothermic and require very high temperature.
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Answer: D
Q772022 · 28 Jul 2022 · Shift 2
White phosphorus reacts with thionyl chloride to give :
1. A. $PC l_{5}$ , $S O_{2}$ and $S_{2} C l_{2}$
2. B. $PC l_{3}$ , $S O_{2}$ and $S_{2} C l_{2}$
3. C. $PC l_{3}$ , $S O_{2}$ and $C l_{2}$
4. D. $PC l_{5}$ , $S O_{2}$ and $C l_{2}$
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Answer: B
Q852022 · 28 Jul 2022 · Shift 2· Numerical answer
A sample of $0.125 g$ of an organic compound when analyzed by Duma's method yields $22.78 mL$ of nitrogen gas collected over $KOH$ solution at $280 K$ and $759 mm Hg$ . The percentage of nitrogen in the given organic compound is ____. (Nearest integer) Given : (a) The vapour pressure of water of $280 K$ is $14.2 mm Hg$ . (b) $R = 0.082 L atm K^{- 1} mo l^{- 1}$
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Answer: 22
Q712022 · 27 Jul 2022 · Shift 1
In Carius method of estimation of halogen, $0.45 g$ of an organic compound gave $0.36 g$ of $AgBr$ . Find out the percentage of bromine in the compound. (Molar masses : $AgBr = 188 g mol^{- 1}; Br = 80 g mol^{- 1}$ )
1. A.34.04%
2. B.40.04%
3. C.36.03%
4. D.38.04%
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Answer: A
Q772022 · 27 Jul 2022 · Shift 1
Which oxoacid of phosphorous has the highest number of oxygen atoms present in its chemical formula?
1. A.Pyrophosphorus acid
2. B.Hypophosphoric acid
3. C.Phosphoric acid
4. D.Pyrophosphoric acid
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Answer: D
Q662022 · 27 Jul 2022 · Shift 2
In neutral or alkaline solution, $Mn O_{4}^{-}$ oxidises thiosulphate to :
1. A. $S_{2} O_{7}^{2 -}$
2. B. $S_{2} O_{8}^{2 -}$
3. C. $S O_{3}^{2 -}$
4. D. $S O_{4}^{2 -}$
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Answer: D
Q712022 · 27 Jul 2022 · Shift 2
1. A.
2. B.
3. C.
4. D.
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Answer: D
Q772022 · 27 Jul 2022 · Shift 2
Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A) : Boron is unable to form $B F_{6}^{3 -}$ . Reason (R) : Size of B is very small. In the light of the above statements, choose the correct answer from the options given below :
1. A.Both (A) and (R) are true and (R) is the correct explanation of (A)
2. B.Both (A) and (R) are true but (R) is not the correct explanation of (A)
3. C.(A) is true but (R) is false
4. D.(A) is false but (R) is true
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Answer: B
Q682022 · 26 Jul 2022 · Shift 1
The difference in the reaction of phenol with bromine in chloroform and bromine in water medium is due to :
1. A.Hyperconjugation in substrate
2. B.Polarity of solvent
3. C.Free radical formation
4. D.Electromeric effect the substrate
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Answer: B
Q812022 · 25 Jul 2022 · Shift 2· Numerical answer
56.0 L of nitrogen gas is mixed with excess hydrogen gas and it is found that 20 L of ammonia gas is produced. The volume of unused nitrogen gas is found to be _________ L.
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Answer: 46
Q672022 · 30 Jun 2022 · Shift 1
$A 573 K Red phosphorus heat ; 803 K under pressure B$ Red phosphorus is obtained by heating "A" at $573 K$ , and can be converted to "B" by heating at $803 K$ under pressure. A and B, respectively, are
1. A. $β$ -black phosphorus and white phosphorus.
2. B.white phosphorus and $β$ -black phosphorus.
3. C. $α$ -black phosphorus and white phosphorus.
4. D.white phosphorus and $α$ -black phosphorus.
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Answer: D
Q872022 · 30 Jun 2022 · Shift 1· Numerical answer
An organic compound with 51.6% sulfur is heated in a Carius tube. The amount of this compound which will form $0.752 g$ of barium sulphate is ___________ $\times 1 0^{- 1} g$ . (Given molar mass of barium sulphate $233 g mol^{- 1}$ ) (Nearest integer).
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Answer: 2
Q762022 · 28 Jun 2022 · Shift 2
Among the given oxides of nitrogen ; $N_{2} O$ , $N_{2} O_{3}$ , $N_{2} O_{4}$ and $N_{2} O_{5}$ , the number of compound/(s) having N - N bond is :
1. A.1
2. B.2
3. C.3
4. D.4
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Answer: C
Q772022 · 28 Jun 2022 · Shift 2
Which of the following oxoacids of sulphur contains "S" in two different oxidation states?
1. A. $H_{2} S_{2} O_{3}$
2. B. $H_{2} S_{2} O_{6}$
3. C. $H_{2} S_{2} O_{7}$
4. D. $H_{2} S_{2} O_{8}$
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Answer: A
Q872022 · 28 Jun 2022 · Shift 2· Numerical answer
The complete combustion of $0.492 g$ of an organic compound containing 'C', 'H' and 'O' gives $0.793 g$ of $C O_{2}$ and $0.442 g$ of $H_{2} O$ . The percentage of oxygen composition in the organic compound is ____. (nearest integer)
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Answer: 46
Q762022 · 27 Jun 2022 · Shift 1
Heating white phosphorus with conc. $NaOH$ solution gives mainly :
1. A. $N a_{3} P$ and $H_{2} O$
2. B. $H_{3} PO$ and $NaH$
3. C. $P (OH)_{3}$ and $Na H_{2} P O_{4}$
4. D. $P H_{3}$ and $Na H_{2} P O_{2}$
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Answer: D
Q772022 · 27 Jun 2022 · Shift 1
Given below are two Statements: Statement I : Classical smog occurs in cool humid climate. It is a reducing mixture of smoke, fog and sulphur dioxide. Statement II : Photochemical smog has components, ozone, nitric oxide, acrolein, formaldehyde, PAN etc. In the light of the above statements, choose the most appropriate answer from the options given below.
1. A.Both Statement I and Statement II are correct.
2. B.Both Statement I and Statement II are incorrect.
3. C.Statement I is correct but Statement II is incorrect.
4. D.Statement I is incorrect but Statement II is correct.
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Answer: A