List of top Chemistry Questions asked in AIIMS

Helium has the highest value of ionisation energy among all the elements known. Helium has the highest value of electron affinity among all the elements known.

Conductivity of silicon increases by doping it with group-15 elements. Doping means introduction of small amount of impurities like $P, As$ or $Bi$ into the pure crystal.

: Chlorine when solidifies does not have zero entropy even at absolute zero. : Chlorine is a pungent smelling gas and it is difficult to solidify it.

: Calcium carbide on hydrolysis gives ethylene. : Calcium carbide contains $C^{4-}$ anions.

Bond energy and bond dissociation energy have identical value for diatomic molecules. Greater the bond dissociation energy, less reactive is the bond.

Benzene on heating with conc. $H_2SO_4$ gives benzenesulphonic acid which when heated with superheated steam under pressure gives benzene. Sulphonation is a reversible process.

A primary amine has higher boiling point than any tertiary amine. A tertiary amine has greater number of $N - H$ bonds for $H$-bonding.

A factory produces $40\, kg$ of calcium in two hours by electrolysis. How much aluminium can be produced by same current in $2 \,hours$ if current efficiency is $50\%$?

$ {A (C10H_18O) ->[{HCL}] P}$

Degree of unsaturation of $A = 2$, it contains no double or triple bonds.

At a certain temperature, the first order rate constant, $k_{1}$ is found to be smaller than the second order rate constant, $k_{2}$. If the energy of activation, $E_{1}$ of the first order reaction is greater than energy of activation, $E_{2}$ of the second order reaction then with increase in temperature

For a first-order reaction $A \rightarrow B$ the plot of $\log \left\{[A]_{t} / 1 M \right\}$ versus $t$ is linear with a

The Brownian motion is due to

$\left[ CoCl _{2}\left( NH _{3}\right)_{4}\right]^{+}+ Cl ^{-} \longrightarrow \left[ CoCl _{3}\left( NH _{3}\right)_{3}\right]+ NH _{3}$ In the reaction only one isomer of complex product is obtained. The initial complex is

$MnO _{4}^{-}$is of intense pink colour, though $Mn$ is in $+7$ oxidation state. It is due to

Consider the sequence of oxides : $Na _{2} O , SiO _{2}$, $P _{4} O _{10}$. Which factor decreases from $Na _{2} O$ to $SiO _{2}$ and also from $SiO _{2}$ to $P _{4} O _{10}$ ?

Which element belongs to $4n$ series?

$0.037\, g$ of an alcohol, $R$-OH was added to $C _{2} H _{5} MgI$ and the gas evolved measured $11.2\, cc$ at STP. The molecular mass of $R- OH$ will be

Decreasing order of stability of ions is (i) $\quad$$CH_3 - C^+H - CH_3$ (ii) $\quad$$CH_3-C^+H-OCH_3$ (iii) $\quad$$CH_3 - C^+H - COCH_3$

For a dilute solution, Raoult's law states that

What is the molarity of $H _{2} SO _{4}$ solution that has a density of $1.84\, g / cc$ at $35^{\circ} C$ and contains $98 \%$ by weight?

To a $25 \,ml \,H _{2} O _{2}$ solution, excess of acidified solution of KI was added. The iodine liberated required $20\, ml$ of $0.3 \,N \,Na _{2} S _{2} O _{3}$ solution.

$2$-Phenylethylbromide when heated with $NaOEt$, elimination takes place. No deuterium exchange takes place when the reaction is carried out in $C_2H_5OD$ solvent. The mechanism will be

Electromeric effect is brought into play only at the requirement of the reagent. It is a temporary effect in which bond pair is shifted to one of the constituent atoms.

How many geometrical isomers are possible in the following two alkenes ? (i) $\quad$$CH_3 - CH = CH - CH = CH - CH_3$ (ii) $\quad$$CH_3 - CH = CH - CH = CH - Cl$

Mercurous chloride exists in the form of