List of top Chemistry Questions

Iodoform can be prepared from all except :

Increasing the temperature of, an aqueous solution will cause

In the electrolysis of alumina to obtain aluminium metal, cryolite is added mainly to

In Bohr?? orbit, $\frac{nh}{2\pi}$ indicates

If $Si$ is doped with $B$,

Gypsum is added to cement to

For 1 mol of an ideal gas at a constant temperature $T$, the plot of $(log\, P)$ against $(log\, V)$ is a ($P$: Pressure, $V$: Volume)

Fire extinguishers contain $H_2SO_4$ and which one of the following?

Extraction of zinc from zinc blende is achieved by

Etherates are

$CsCl$ has $bcc$ arrangement. Its unit cell edge length is $400\,pm$. Its inter-ionic distance is

But-1-ene $ { ->[{(CH_3COO)_2Hg}][{H_3O^+}] }$ ? The product in the above reaction is

Bond dissociation energy of CH is 360 kJ/mol and CH is 620 kJ/mol. Then bond dissociation energy of C - C bond is

Bakelite is obtained from phenol by reacting it with

van-Arkel method is used to prepare samples of some metals. It involves reaction of $CO$ with metals to form volatile carbonyls which decompose on heating to give pure metal.

The presence of nitro group facilitates nucleophilic substitution reactions in aryl halides. The intermediate carbanion is stabilised due to the presence of nitro group.

The free gaseous Cr atom has six unpaired electrons. Half-filled s-orbital has greater stability.

Sodium acetate on Kolbe?? electrolysis gives methane. Methyl free radical is formed at cathode.

Sodium carbonate extract of a salt containing sulphide ions gives a violet colour with appropriate reagent. The reagent sodium nitroprusside gives violet colour due to the formation of sodium thionitroprusside.

Precipitation of soap is made by the addition of salt $(NaCl)$. Presence of common ion suppresses the dissociation of weak acid.

Phenol is more reactive than benzene towards electrophilic substitution reaction. In the case of phenol, the intermediate carbocation is more resonance stabilised.

HC $=$ C$^{-}$ is more stable than HC $=$ CH$^{-}$. HC $=$ C$^{-}$ has more s-character than HC $=$ CH$^{-}$.

$H_2Se$ is less acidic than $H_2S$. $S$ is less electronegative than $Se$.

$[Fe(H_2O)_5NO]SO_4$ is paramagnetic. The $Fe$ in $[Fe(H_2O)_5NO]SO_4$ has three unpaired electrons.

Diamond and graphite do not have the same crystal structure. Diamond is crystalline while graphite is amorphous.