p-Block Elements · JEE Main previous year questions

The complete combustion of $0.492\mathrm{g}$ of an organic compound containing 'C', 'H' and 'O' gives $0.793\mathrm{g}$ of $\mathrm{C}{\mathrm{O}}_2$ and $0.442\mathrm{g}$ of ${\mathrm{H}}_2\mathrm{O}$. The percentage of oxygen composition in the organic compound is ____. (nearest integer)

Heating white phosphorus with conc. $\mathrm{NaOH}$ solution gives mainly :

1. A.$\mathrm{N}{\mathrm{a}}_3\mathrm{P}$ and ${\mathrm{H}}_2\mathrm{O}$
2. B.${\mathrm{H}}_3\mathrm{PO}$ and $\mathrm{NaH}$
3. C.$\mathrm{P}(\mathrm{OH}{)}_3$ and $\mathrm{Na}{\mathrm{H}}_2\mathrm{P}{\mathrm{O}}_4$
4. D.$\mathrm{P}{\mathrm{H}}_3$ and $\mathrm{Na}{\mathrm{H}}_2\mathrm{P}{\mathrm{O}}_2$

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.

Given below are two statements : one is labelled as Assertion A and the other is labelled as Reason R. Assertion A : Fluorine forms one oxoacid. Reason R : Fluorine has smallest size amongst all halogens and is highly electronegative. In the light of the above statements, choose the most appropriate answer from the options given below :

1. A.Both A and R are correct and R is the correct explanation of A.
2. B.Both A and R are correct but R is NOT the correct explanation of A.
3. C.A is correct but R is not correct.
4. D.A is not correct but R is correct.

$116\text{ g}$ of a substance upon dissociation reaction, yields $7.5\text{ g}$ of hydrogen, $60\text{ g}$ of oxygen and $48.5\text{ g}$ of carbon. Given that the atomic masses of H, O and C are $1$, $16$ and $12$, respectively. The data agrees with how many formulae of the following? A. ${\text{CH}}_3\text{COOH}$, B. $\text{HCHO}$, C. ${\text{CH}}_3{\text{OOCH}}_3$, D. ${\text{CH}}_3\text{CHO}$

$0.25\text{ g}$ of an organic compound containing chlorine gave $0.40\text{ g}$ of silver chloride in Carius estimation. The percentage of chlorine present in the compound is ________. [in nearest integer] (Given : Molar mass of Ag is $108{\text{ g mol}}^{-1}$ and that of Cl is $35.5{\text{ g mol}}^{-1}$)

Given below are two statements : Statement I : In 'Lassaigne's Test', when both nitrogen and sulphur are present in an organic compound, sodium thiocyanate is formed. Statement II : If both nitrogen and sulphur are present in an organic compound, then the excess of sodium used in sodium fusion will decompose the sodium thiocyanate formed to give $\mathrm{NaCN}$ and $\mathrm{N}{\mathrm{a}}_2\mathrm{S}$. 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.

Consider the following reaction : $\text{A + alkali}\to \text{B (Major Product)}$ If B is an oxoacid of phosphorus with no P-H bond, then A is :

1. A.White ${\mathrm{P}}_4$
2. B.Red ${\mathrm{P}}_4$
3. C.${\mathrm{P}}_2{\mathrm{O}}_3$
4. D.${\mathrm{H}}_3{\mathrm{PO}}_3$

The oxide which contains an odd electron at the nitrogen atom is :

1. A.${\mathrm{N}}_2\mathrm{O}$
2. B.$\mathrm{N}{\mathrm{O}}_2$
3. C.${\mathrm{N}}_2{\mathrm{O}}_3$
4. D.${\mathrm{N}}_2{\mathrm{O}}_5$

1. A.
2. B.
3. C.
4. D.

CNG is an important transportation fuel. When $100\mathrm{g}$ CNG is mixed with $208\mathrm{g}$ oxygen in vehicles, it leads to the formation of $\mathrm{C}{\mathrm{O}}_2$ and ${\mathrm{H}}_2\mathrm{O}$ and produces large quantity of heat during this combustion, then the amount of carbon dioxide, produced in grams is ____. [nearest integer] [Assume CNG to be methane]

White precipitate of $\mathrm{AgCl}$ dissolves in aqueous ammonia solution due to formation of :

1. A.$[\mathrm{Ag}({\mathrm{NH}}_3{)}_4]{\mathrm{Cl}}_2$
2. B.$[\mathrm{Ag}(\mathrm{Cl}{)}_2({\mathrm{NH}}_3{)}_2]$
3. C.$[\mathrm{Ag}({\mathrm{NH}}_3{)}_2]\mathrm{Cl}$
4. D.$[\mathrm{Ag}({\mathrm{NH}}_3)\mathrm{Cl}]\mathrm{Cl}$

Cerium (IV) has a noble gas configuration. Which of the following is correct statement about it?

1. A.It will not prefer to undergo redox reactions.
2. B.It will prefer to gain electron and act as an oxidizing agent.
3. C.It will prefer to give away an electron and behave as reducing agent.
4. D.It acts as both, oxidizing and reducing agent.

Phenol on reaction with dilute nitric acid, gives two products. Which method will be most efficient for large scale separation?

1. A.Chromatographic separation
2. B.Fractional Crystallisation
3. C.Steam distillation
4. D.Sublimation

1. A.
2. B.
3. C.
4. D.

Leaching of gold with dilute aqueous solution of $\mathrm{NaCN}$ in presence of oxygen gives complex [A], which on reaction with zinc forms the elemental gold and another complex [B]. [A] and [B], respectively are :

1. A.$[Au(CN{)}_4{]}^{-}$ and $[Zn(CN{)}_2(OH{)}_2{]}^{2-}$
2. B.$[Au(CN{)}_2{]}^{-}$ and $[Zn(OH{)}_4{]}^{2-}$
3. C.$[Au(CN{)}_2{]}^{-}$ and $[Zn(CN{)}_4{]}^{2-}$
4. D.$[Au(CN{)}_4{]}^{2-}$ and $[Zn(CN{)}_6{]}^{4-}$

Number of grams of bromine that will completely react with $5.0\text{ g}$ of pent-1-ene is $\underline{}\times 10^{-2}\text{ g}$. (Atomic mass of $\mathrm{Br}=80\text{ g/mol}$) [Nearest Integer]

The number of bridged oxygen atoms present in compound B formed from the following reactions is $\mathrm{Pb}(\mathrm{N}{\mathrm{O}}_3{)}_2\stackrel{673\mathrm{K}}{\to }\mathrm{A}+\mathrm{PbO}+{\mathrm{O}}_2$ $\mathrm{A}\stackrel{\mathrm{Dimerise}}{\to }\mathrm{B}$

1. A.0
2. B.1
3. C.2
4. D.3

A rigid nitrogen tank stored inside a laboratory has a pressure of $30\mathrm{atm}$ at 06:00 am when the temperature is $27^{\circ }\mathrm{C}$. At 03:00 pm, when the temperature is $45^{\circ }\mathrm{C}$, the pressure in the tank will be ____ $\mathrm{atm}$. [nearest integer]

The oxide without nitrogen-nitrogen bond is :

1. A.${\mathrm{N}}_2\mathrm{O}$
2. B.${\mathrm{N}}_2{\mathrm{O}}_4$
3. C.${\mathrm{N}}_2{\mathrm{O}}_3$
4. D.${\mathrm{N}}_2{\mathrm{O}}_5$

Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A) : Photochemical smog causes cracking of rubber. Reason (R) : Presence of ozone, nitric oxide, acrolein, formaldehyde and peroxyacetyl nitrate in photochemical smog makes it oxidizing. Choose the most appropriate answer from the options given below :

1. A.Both (A) and (R) are true but (R) is not the true explanation of (A)
2. B.(A) is false but (R) is true.
3. C.(A) is true but (R) is false.
4. D.Both (A) and (R) are true and (R) is the true explanation of (A)

In the sulphur estimation, 0.471 g of an organic compound gave 1.44 g of barium sulphate. The percentage of sulphur in the compound is ____________%. (Nearest integer) (Atomic Mass of Ba = 137 u)

Match List - I with List - II : | | List - I (compound) | | List - II (effect/affected species) | |---|---|---|---| | (a) | Carbon monoxide | (i) | Carcinogenic | | (b) | Sulphur dioxide | (ii) | Metabolized by pyrus plants | | (c) | Polychlorinated biphenyls | (iii) | haemoglobin | | (d) | Oxides of Nitrogen | (iv) | Stiffness of flower buds | Choose the correct answer from the options given below :

1. A.(a) - (iii), (b) - (iv), (c) - (i), (d) - (ii)
2. B.(a) - (iv), (b) - (i), (c) - (iii), (d) - (ii)
3. C.(a) - (i), (b) - (ii), (c) - (iii), (d) - (iv)
4. D.(a) - (iii), (b) - (iv), (c) - (ii), (d) - (i)

[structure: phenol] $⟶$ [structure: p-bromophenol] (Major Product) The given reaction can occur in the presence of : (a) Bromine water (b) $\mathrm{B}{\mathrm{r}}_2$ in $\mathrm{C}{\mathrm{S}}_2$, 273 K (c) $\mathrm{B}{\mathrm{r}}_2/FeB{\mathrm{r}}_3$ (d) $\mathrm{B}{\mathrm{r}}_2$ in $\mathrm{CHC}{\mathrm{l}}_3$, 273 K Choose the correct answer from the options given below :

1. A.(b) and (d) only
2. B.(a) and (c) only
3. C.(b), (c) and (d) only
4. D.(a), (b) and (d) only

Given below are two statements : Statement I : Chlorofluoro breakdown by radiation in the visible energy region and release chlorine gas in the atmosphere which then reacts with stratospheric ozone. Statement II : Atmospheric ozone reacts with nitric oxide to give nitrogen and oxygen gases, which add to the atmosphere. For the above statements choose the correct answer from the options given below :

1. A.Statement I is incorrect but Statement II is true
2. B.Both Statement I and II are false
3. C.Statement I is correct but Statement II is false
4. D.Both Statement I and II are correct