p-Block Elements · JEE Main previous year questions

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2010 1 question

Q792010 · 25 Apr 2010 · Shift 1
29.5 mg of an organic compound containing nitrogen was digested according to Kjeldahl’s method and the evolved ammonia was absorbed in 20 mL of 0.1 M HCl solution. The excess of the acid required 15 mL of 0.1 M NaOH solution for complete neutralization. The percentage of nitrogen in the compound is
1. A.59.0
2. B.47.4
3. C.23.7
4. D.29.5
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Answer: C

2009 1 question

Q892009 · 27 Apr 2009 · Shift 1
Which one of the following reactions of Xenon compounds is not feasible?
1. A. $Xe O_{3} + 6HF \to Xe F_{6} + 3 H_{2} O$
2. B. $Xe F_{6} + RbF \to Rb [Xe F_{7}]$
3. C. $2Xe F_{2} + 2 H_{2} O \to 2Xe + 4HF + O_{2}$
4. D. $3Xe F_{4} + 6 H_{2} O \to 2Xe + Xe O_{3} + 12HF + 1.5 O_{2}$
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Answer: A

2006 3 questions

Q1072006 · 29 Apr 2006 · Shift 1
The enthalpy changes for the following processes are listed below : $C l_{2} (g) = 2Cl (g), 242.3 kJ mo l^{- 1}$ $I_{2} (g) = 2I (g), 151.0 kJ mo l^{- 1}$ $ICl (g) = I (g) + Cl (g), 211.3 kJ mo l^{- 1}$ $I_{2} (s) = I_{2} (g), 62.76 kJ mo l^{- 1}$ Given that the standard states for iodine and chlorine are $I_{2} (s)$ and $C l_{2} (g)$ , the standard enthalpy of formation for $ICl (g)$ is :
1. A. $- 14.6 kJ mo l^{- 1}$
2. B. $- 16.8 kJ mo l^{- 1}$
3. C. $+ 16.8 kJ mo l^{- 1}$
4. D. $+ 244.8 kJ mo l^{- 1}$
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Answer: C
Q1082006 · 29 Apr 2006 · Shift 1
$(Δ H - Δ U)$ for the formation of carbon monoxide (CO) from its elements at $298 K$ is : ( $R = 8.314 J K^{- 1} mo l^{- 1}$ )
1. A. $- 1238.78 J mo l^{- 1}$
2. B. $1238.78 J mo l^{- 1}$
3. C. $- 2477.57 J mo l^{- 1}$
4. D. $2477.57 J mo l^{- 1}$
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Answer: B
Q1432006 · 29 Apr 2006 · Shift 1
1. A.
2. B.
3. C.
4. D.
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Answer: C

2005 8 questions

Q1702005 · 28 Apr 2005 · Shift 1
2-methylbutane on reacting with bromine in the presence of sunlight gives mainly
1. A.1-bromo-2-methylbutane
2. B.2-bromo-2-methylbutane
3. C.2-bromo-3-methylbutane
4. D.1-bromo-3-methylbutane
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Answer: B
Q1942005 · 28 Apr 2005 · Shift 1
Elimination of bromine from 2-bromobutane results in the formation of-
1. A.equimolar mixture of 1 and 2-butene
2. B.predominantly 2-butene
3. C.predominantly 1-butene
4. D.predominantly 2-butyne
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Answer: B
Q2002005 · 28 Apr 2005 · Shift 1
An organic compound having molecular mass 60 is found to contain $C = 20%$ , $H = 6.67%$ and $N = 46.67%$ while rest is oxygen. On heating it gives $N H_{3}$ along with a solid residue. The solid residue give violet colour with alkaline copper sulphate solution. The compound is
1. A. $C H_{3} NCO$
2. B. $C H_{3} CON H_{2}$
3. C. $(N H_{2})_{2} CO$
4. D. $C H_{3} C H_{2} CON H_{2}$
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Answer: C
Q2092005 · 28 Apr 2005 · Shift 1
The molecular shapes of $S F_{4}$ , $C F_{4}$ and $Xe F_{4}$ are
1. A.the same with 2,0 and 1 lone pairs of electrons on the central atom, respectively
2. B.the same with 1, 1 and 1 lone pair of electrons on the central atoms, respectively
3. C.different with 0, 1 and 2 lone pair of electrons on the central atoms, respectively
4. D.different with 1, 0 and 2 lone pairs of electron on the central atoms respectively
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Answer: D
Q2182005 · 28 Apr 2005 · Shift 1
The number of hydrogen atom(s) attached to phosphorus atom in hypophosphorous acid is :
1. A.zero
2. B.two
3. C.one
4. D.three
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Answer: B
Q2202005 · 28 Apr 2005 · Shift 1
Heating an aqueous solution of aluminium chloride to dryness will give :
1. A. $AlC l_{3}$
2. B. $A l_{2} C l_{6}$
3. C. $A l_{2} O_{3}$
4. D. $Al (OH) C l_{2}$
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Answer: C
Q2212005 · 28 Apr 2005 · Shift 1
In silicon dioxide :
1. A.Each silicon atom is surrounded by four oxygen atoms and each oxygen atom is bonded to two silicon atoms
2. B.Each silicon atom is surrounded by two oxygen atoms and each oxygen atom is bonded to two silicon atoms
3. C.Silicon atoms is bonded to two oxygen atoms
4. D.there are double bonds between silicon and oxygen atoms
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Answer: A
Q2222005 · 28 Apr 2005 · Shift 1
The structure of diborane ( $B_{2} H_{6}$ ) contains :
1. A.four 2c-2e bonds and two 3c-2e bonds
2. B.two 2c-2e bonds and four 3c-2e bonds
3. C.two 2c-2e bonds and two 3c-3e bonds
4. D.four 2c-2e bonds and four 3c-2e bonds
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Answer: A

2004 4 questions

Q1492004 · 24 Apr 2004 · Shift 1
The ammonia evolved from the treatment of 0.30 g of an organic compound for the estimation of nitrogen was passed in 100 mL of 0.1 M sulphuric acid. The excess of acid required 20 mL of 0.5 M sodium hydroxide solution for complete neutralization. The organic compound is
1. A.urea
2. B.benzamide
3. C.acetamide
4. D.thiourea
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Answer: A
Q1592004 · 24 Apr 2004 · Shift 1
The states of hybridization of boron and oxygen atoms in boric acid ( $H_{3} B O_{3}$ ) are respectively
1. A. $s p^{2}$ and $s p^{2}$
2. B. $s p^{3}$ and $s p^{3}$
3. C. $s p^{3}$ and $s p^{2}$
4. D. $s p^{2}$ and $s p^{3}$
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Answer: D
Q2172004 · 24 Apr 2004 · Shift 1
Which among the following factors is the most important in making fluorine the strongest oxidizing halogen?
1. A.Electron affinity
2. B.Bond dissociation energy
3. C.Hydration enthalpy
4. D.Ionization enthalpy
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Answer: C
Q2182004 · 24 Apr 2004 · Shift 1
Aluminium chloride exists as dimer, $A l_{2} C l_{6}$ in solid state as well as in solution of non-polar solvents such as benzene. When dissolved in water, it gives :
1. A. $A l^{3 +} + 3C l^{-}$
2. B. $A l_{2} O_{3} + 6HCl$
3. C. $[Al (OH)_{6}]^{3 -}$
4. D. $[Al (H_{2} O)_{6}]^{3 +} + 3C l^{-}$
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Answer: D

2002 1 question

Q2212002 · 27 Apr 2002 · Shift 1
In case of nitrogen, $NC l_{3}$ is possible but not NCl5 while in case of phosphorous, $PC l_{3}$ as well as $PC l_{5}$ are possible. It is due to :
1. A.availability of vacant d orbitals in P but not in N
2. B.lower electronegativity of P than N
3. C.lower tendency of H - bond formation in P than N
4. D.occurrence of P in solid while N in gaseous state at room temperature
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Answer: A