Other Chemistry · JEE Main previous year questions

Given below are two statements : Statement I : Both $\mathrm{CaC}{\mathrm{l}}_2\cdot 6{\mathrm{H}}_2\mathrm{O}$ and $\mathrm{MgC}{\mathrm{l}}_2\cdot 8{\mathrm{H}}_2\mathrm{O}$ undergo dehydration on heating. Statement II : $\mathrm{BeO}$ is amphoteric whereas the oxides of other elements in the same group are acidic. In the light of the above statements, choose the correct answer from the options given below :

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

$2\mathrm{Mn}{\mathrm{O}}_4^{-}+b{\mathrm{C}}_2{\mathrm{O}}_4^{2-}+c{\mathrm{H}}^{+}\to x\mathrm{M}{\mathrm{n}}^{2+}+y\mathrm{C}{\mathrm{O}}_2+z{\mathrm{H}}_2\mathrm{O}$ If the above equation is balanced with integer coefficients, the value of c is _______. (Round off to the Nearest Integer).

Which of the following is 'a' FALSE statement ?

1. A.Carius method is used for the estimation of nitrogen in an organic compound.
2. B.Kjeldahl's method is used for the estimation of nitrogen in an organic compound.
3. C.Carius tube is used in the estimation of sulphur in an organic compound.
4. D.Phosphoric acid produced on oxidation of phosphorus present in an organic compound is precipitated as $\mathrm{M}{\mathrm{g}}_2{\mathrm{P}}_2{\mathrm{O}}_7$ by adding magnesia mixture.

On treating a compound with warm dil. ${\mathrm{H}}_2\mathrm{S}{\mathrm{O}}_4$, gas X is evolved which turns ${\mathrm{K}}_2\mathrm{C}{\mathrm{r}}_2{\mathrm{O}}_7$ paper acidified with dil. ${\mathrm{H}}_2\mathrm{S}{\mathrm{O}}_4$ to a green compound Y. X and Y respectively are :

1. A.$\mathrm{X}=\mathrm{S}{\mathrm{O}}_2,\mathrm{Y}=\mathrm{C}{\mathrm{r}}_2{\mathrm{O}}_3$
2. B.$\mathrm{X}=\mathrm{S}{\mathrm{O}}_3,\mathrm{Y}=\mathrm{C}{\mathrm{r}}_2(\mathrm{S}{\mathrm{O}}_4{)}_3$
3. C.$\mathrm{X}=\mathrm{S}{\mathrm{O}}_3,\mathrm{Y}=\mathrm{C}{\mathrm{r}}_2{\mathrm{O}}_3$
4. D.$\mathrm{X}=\mathrm{S}{\mathrm{O}}_2,\mathrm{Y}=\mathrm{C}{\mathrm{r}}_2(\mathrm{S}{\mathrm{O}}_4{)}_3$

The number of significant figures in $50000.020\times 10^{-3}$ is _________.

Which of the following forms of hydrogen emits low energy ${\beta }^{-}$ particles?

1. A.Tritium ${}_1^3\mathrm{H}$
2. B.Proton ${\mathrm{H}}^{+}$
3. C.Protium ${}_1^1\mathrm{H}$
4. D.Deuterium ${}_1^2\mathrm{H}$

Which pair of oxides is acidic in nature?

1. A.$\mathrm{CaO},\mathrm{Si}{\mathrm{O}}_2$
2. B.${\mathrm{B}}_2{\mathrm{O}}_3,\mathrm{CaO}$
3. C.${\mathrm{B}}_2{\mathrm{O}}_3,\mathrm{Si}{\mathrm{O}}_2$
4. D.${\mathrm{N}}_2\mathrm{O},\mathrm{BaO}$

2, 4-DNP test can be used to identify :

1. A.ether
2. B.amine
3. C.aldehyde
4. D.halogens

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

Calgon is used for water treatment. Which of the following statement is NOT true about Calgon?

1. A.It is also known as Graham's salt.
2. B.It is polymeric compound and is water soluble.
3. C.It does not remove $\mathrm{C}{\mathrm{a}}^{2+}$ ion by precipitation.
4. D.Calgon contains the $2^{\text{nd}}$ most abundant element by weight in the Earth's crust.

Emf of the following cell at 298K in V is $x\times 10^{-2}$. $Zn|Z{\mathrm{n}}^{2+}(0.1\mathrm{M})||A{\mathrm{g}}^{+}(0.01\mathrm{M})|Ag$ The value of x is _________. (Rounded off to the nearest integer) [Given : $E_{\mathrm{Z}{\mathrm{n}}^{2+}/Zn}^{\theta }=-0.76\mathrm{V}$; $E_{\mathrm{A}{\mathrm{g}}^{+}/Ag}^{\theta }=+0.80\mathrm{V}$; $\frac{2.303RT}{F}=0.059$]

The $\mathrm{NaN}{\mathrm{O}}_3$ weighed out to make 50 mL of an aqueous solution containing $70.0\mathrm{mg}\mathrm{N}{\mathrm{a}}^{+}$ per mL is _________ g. (Rounded off to the nearest integer) $[\text{Given : Atomic weight in }\mathrm{g}\mathrm{mo}{\mathrm{l}}^{-1}\text{ - }\mathrm{Na}:23;\mathrm{N}:14;\mathrm{O}:16]$

1. A.$\text{IV}>\text{III}>\text{II}>\text{I}$
2. B.$\text{III}>\text{II}>\text{I}>\text{IV}$
3. C.$\text{II}>\text{III}>\text{IV}>\text{I}$
4. D.$\text{I}>\text{II}>\text{III}>\text{IV}$

Water does not produce $\mathrm{CO}$ on reacting with :

1. A.$\mathrm{C}$
2. B.$\mathrm{C}{\mathrm{H}}_4$
3. C.${\mathrm{C}}_3{\mathrm{H}}_8$
4. D.$\mathrm{C}{\mathrm{O}}_2$

The major components of German Silver are :

1. A.Zn, Ni and Ag
2. B.Cu, Zn and Ni
3. C.Cu, Zn and Ag
4. D.Ge, Cu and Ag

Which one of the following statements is FALSE for hydrophilic sols?

1. A.They do not require electrolytes for stability.
2. B.The sols cannot be easily coagulated.
3. C.These sols are reversible in nature.
4. D.Their viscosity is of the order of that of ${\mathrm{H}}_2\mathrm{O}$.

1. A.$\text{I}<\text{II}<\text{IV}<\text{III}$
2. B.$\text{I}<\text{II}<\text{III}<\text{IV}$
3. C.$\text{II}<\text{I}<\text{III}<\text{IV}$
4. D.$\text{II}<\text{IV}<\text{III}<\text{I}$

The incorrect statement is :

1. A.bronze is an alloy of copper and tin
2. B.cast iron is used to manufacture wrought iron
3. C.german silver is an alloy of zinc, copper and nickel
4. D.brass is an alloy of copper and nickel

Kraft temperature is the temperature :

1. A.below which the aqueous solution of detergents starts freezing.
2. B.above which the formation of micelles takes place.
3. C.below which the formation of micelles takes place.
4. D.above which the aqueous solution of detergents starts boiling.

The number of Cl = O bonds in perchloric acid is, "________".

A spherical balloon of radius $3\text{ cm}$ containing helium gas has a pressure of $48\times 10^{-3}\text{ bar}$. At the same temperature, the pressure, of a spherical balloon of radius $12\text{ cm}$ containing the same amount of gas will be ______ $\times 10^{-6}\text{ bar}$.

Which one of the following statements is not true?

1. A.Lactose contains $\alpha$-glycosidic linkage between ${\mathrm{C}}_1$ of galactose and ${\mathrm{C}}_4$ of glucose
2. B.Lactose is a reducing sugar and it gives Fehling’s test
3. C.On acid hydrolysis, lactose gives one molecule of D(+)-glucose and one molecule of D(+)-galactose
4. D.Lactose (${\mathrm{C}}_{12}{\mathrm{H}}_{22}{\mathrm{O}}_{11}$) is a disaccharide and it contains 8 hydroxyl groups

Mischmetal is an alloy consisting mainly of :

1. A.lanthanoid and actinoid metals
2. B.actinoid and transition metals
3. C.lanthanoid metals
4. D.actinoid metals

A set of solutions is prepared using 180 g of water as a solvent and 10 g of different nonvolatile solutes A, B and C. The relative lowering of vapour pressure in the presence of these solutes are in the order : $[\text{Given, molar mass of }\mathrm{A}=100\mathrm{g}\mathrm{mo}{\mathrm{l}}^{-1};\mathrm{B}=200\mathrm{g}\mathrm{mo}{\mathrm{l}}^{-1};\mathrm{C}=10,000\mathrm{g}\mathrm{mo}{\mathrm{l}}^{-1}]$

1. A.$\text{A}>\text{C}>\text{B}$
2. B.$\text{C}>\text{B}>\text{A}$
3. C.$\text{A}>\text{B}>\text{C}$
4. D.$\text{B}>\text{C}>\text{A}$

The reaction of NO with ${\mathrm{N}}_2{\mathrm{O}}_4$ at 250 K gives :

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