List of top Chemistry Questions

If at 298 K the bond energies of C-H, C-C, C = C and H-H bonds are respectively 414, 347, 615 and 435 kJ $mol^{-1}$ the value of enthalpy change for the reaction.$H_2C = CH_2(g) + H_2(g) -----> H_3C-CH_3(g)$ at 298 K will be

Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R
Assertion (A) : For extraction of Iron haematite ore is used.

Reason (R) : Because haematite is carbonate ore.

In the light of the above statements, choose the correct answer from the options given below

Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R
Assertion (A) : H-S-H bond angle in H$_2$S is closer to 90$^{\circ}$ but H-0-H bond angle in H$_2O$ is 104.5$^{\circ}$.

Reason (R) : $lp-lp$ repulsion is stronger in $H_2S$ than in H$_2O$.

In the light of the above statements, choose the correct answer from the options given below

Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R
Assertion (A): London smog is oxidising in nature.

Reason (R): London smog contains O$_3$, NO$_2$ and hydrocarbons.

In the light of the above statements, choose the correct answer from the options given below

Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R
Assertion (A): On cooling, ammonia liquifies first whereas $CO_{2}$ requires more cooling.

Reason (R): Critical temperatures of ammonia and carbon dioxide are $405.5 K$ and $304.10 K$ respectively.

In the light of the above statements, choose the correct answer from the options given below

Which of the following have identical bond order? (I) $CN^-$$\quad$ (II) $O_2 ^-$ $\quad$(III) $NO^+$$\quad$ (IV) $CN^+$

The correct order of energy of absorption for the following metal complexes is $A :\left[ Ni ( en )_3\right]^{2+}$, $ B :\left[ Ni \left( NH _3\right)_6\right]^{2+}$, $C :\left[ Ni \left( H _2 O \right)_6\right]^{2+}$

The minimum energy in electron volt required to strip off ten times ionized sodium atom (i.e. Z = 11) of its last electron is

When $H_2O_2$ is added to an acidified $K_2Cr_2O_7$ solution

Mendius reaction involves the reduction of

Cheilosis and digestive disorders are due to the deficiency of

The first artificial disintegration of an atomic nucleus was achieved by:

A group of 13 element if added in small amounts to Ge, then the type of semiconductor formed is

The number and type of bonds between two carbon atoms in $CaC_2$ are

Oxygen does not form $OF_6$ because