List of top Chemistry Questions asked in AIIMS

Consider the following set of reactions : $ {CH3COOH ->[SOCl_2] A}$$ { ->[Benzene][Anhyd. AlCl_3] B}$$ { ->[HCN] C}$$ { ->[HOH] D}$ The structure of D would be

Calculate the overall complex dissociation equilibrium constant for the $[Cu(NH_3)_4]^{2+}$ ions, given that stability constant ($\beta$) for this complex is $2.1 \times 10^{13}$.

trans-Pent-2-ene is polar but trans- but-2-ene is non-polar. The polarity of cis-isomer is more than trans-isomer, which are either non-polar or less polar.

The number of tetrahedral voids is double the number of octahedral voids. The size of the tetrahedral voids is half of that of the octahedral void.

Hydrides of group-16 elements show volatility in the order : $H_2O > H_2S > H_2Se > H_2Te$ Electronegativity of group-16 elements increases down the group from oxygen to tellurium.

$[Fe(CN)_6]^{3-}$ has $d^2sp^3$ type hybridisation. $[Fe(CN)_6]^{3-}$ ion shows magnetic moment corresponding to two unpaired electrons.

Aromatic aldehydes and formaldehyde undergo Cannizzaro reaction. Aromatic aldehydes are almost as reactive as formaldehyde.

Which of the following compounds is aromatic in nature?

On the basis of standard electrode potential of redox couples given below, find out which of the following is the strongest oxidising agent. (E$^{\circ}$ values : $Fe^{3+}\left| Fe^{2+}=+ 0.77 V ; I_{2\left(s\right)}\right|I^{- } =$ $+ 0.54 V; Cu^{2+}\left|Cu= + .34 V ; Ag^{+}\right| Ag = + 0.80 V$)

$H_2O$ is polar, whereas $BeF_2$ is not because

Chlorobenzene is more reactive than benzene towards the electrophilic substitution reaction. Resonance destabilises the carbocation.

Among the following, the achiral amino acid is

$K_p$ for the reaction $ {A {\rightleftharpoons} B}$ is 4. If initially only A is present then what will be the partial pressure of B after equilibrium ?

Select the correct statement

Which of the following reactions does not take place? $ {BF3 + F^{-} ->BF4^{-}}$$\quad\quad\quad\quad\quad\quad\quad\quad\ldots\left(I\right)$ $ {BF3 + 3F^{-} ->BF6^{3-}}$$\quad\quad\quad\quad\quad\quad\quad\ldots\left(II\right)$ $ {AlF3 + 3F^{-} ->AlF6^{3-}}$$\quad\quad\quad\quad\quad\quad\ldots\left(III\right)$

Which of the following species is not aromatic?

Which of the following can be oxidised by $SO_2$ ?

Two elements $A$ and $B$ form compounds of formula $AB_2$ and $AB_4$. When dissolved in $20.0\, g$ of benzene $1.0 \,g$ of $AB_2$ lowers f. pt. by 2.3$^{\circ}$C whereas $1.0\, g$ of $AB_4$ lowers f. pt. by 1.3$^{\circ}$C. The $K_f$ for benzene is $5.1$. The atomic masses of $A$ and $B$ are

The reaction, $C_6H_5ONa + CO_2 + H_2O \to C_6H_5OH + NaHCO_3$ suggests that

Oil used as frothing agent in froth floatation process is

If an atom crystallises in bcc lattice with r = 4 $?? then the edge length will be

Best reagent for the conversion of $AgNO_3$ to Ag is

When acetamide reacts with $NaOH$ and $Br_2$, methyl amine is formed. The reaction occurs through intermediate formation of isocyanate.

Staggered conformation of ethane is $12.5\, kJ\, mol^{-1}$ more stable than the eclipsed conformation. The two conformations of ethane cannot be separated at room temperature.

Diamagnetic substances are not attracted by magnetic field. Diamagnetic substances have no unpaired electrons.