List of top Chemistry Questions

For the element $O$ or $F$, the electron gain enthalpy is less negative than that of the succeeding element. Electron gain enthalpy becomes less negative as we go down a group.

$[Fe(H_{2}O ) _{6}]^{3+}$ is strongly paramagnetic whereas $[Fe(CN)_{6}]^{3-}$ is weakly paramagnetic. $H_{2}O$ is a weak field ligand and $CN^{-}$ is a strong field ligand.

Diamond is the hardest substance on the earth. It has high melting point.

Decomposition of hydrogen peroxide is an example of disproportionation reaction. In a disproportionation reaction, an element in one oxidation state is simultaneously oxidised and reduced.

$CsCl$ has body-centred cubic arrangement. $CsCl$ has one $Cs^+$ ion and $8\, Cl^-$ ions in its unit cell.

Cresols are less acidic than phenol. Electron releasing groups do not favour the formation of phenoxide ion.

$Cr^{2+}$ is reducing and $Mn^{3+}$ is oxidising. $Cr^{2+}$ and $Mn^{3+}$ have $d^4$ configuration.

Copper dissolves in dilute nitric acid but not in dilute $HCl$. Copper has positive $E^?$.

CO and CN are referred as $\pi$ acid ligands. In CO and CN vacant $\pi$ type orbitals are present.

Common name of $1,1$-dichloroethane is ethylidene chloride. Ethylidene chloride is a gem-dihalide.

Classical smog is oxidising smog whereas photochemical smog is reducing smog. Classical smog occurs in warm, dry and sunny climate whereas photochemical smog occurs in cool humid climate.

$CO_{2}$ is a gas at room temperature while $SiO_{2}$ is a crystalline solid. $SiO_{2}$ is a network of silicon and oxygen atoms joined by multiple bonds.

$CH_{2} = C H ??H_{2}??$ is an example of allyl halides. These are the compounds in which the halogen atom is bonded to an $sp^{2}$ hybridised carbon atom.

Catenation tendency is weaker in nitrogen. Nitrogen exists as diatomic gas.

Carbon atom is tetravalent though it has two unpaired electrons. Carbon has unique ability to form $p\pi-p\pi$ multiple bonds with itself like $C=C, C\equiv C$.

Carbon monoxide is a poisonous gas. Carbon monoxide combines with haemoglobin to form carboxy-haemoglobin which prevents absorption of oxygen by it.

Buna-$S$ is a copolymer. Buna-$S$ is formed by condensation reaction between two different monomers.

Boron is metalloid Boron shows metallic nature.

Atomic number of the element ununtrium is 113. According to $IUPAC$ system of nomenclature, the numerical roots for $1,1$ and $3$ are un, un and tri respectively.

At high altitudes, liquids boil at lower temperatures in comparison to that at sea level. At high altitudes, atmospheric pressure is low.

Aryl halides are highly reactive towards nucleophilic substitution reactions. In case of haloarenes, halogen atom is attached to sp hybridised carbon atom.

Ammonia acts as a ligand. A lone pair of electrons on nitrogen can be donated to acceptor.

$3d_{z^{2}}$ orbital is spherically symmetrical. The shapes of all five $d$-orbitals are similar to each other.

Aspartame, the artificial sweetener is made by a dipeptide of the amino acids,

Ascorbic acid is the chemical name of