List of top Chemistry Questions

Addition of group-13 elements to intrinsic semiconductors results in

When a substance ' $A$ ' reacts with water, it produces a combustible gas ' $B$ ' and a solution of substance ' $C$ ' in water. while another substance ' $D$ ' reacts with solution of ' $C$ ' to produce the same gas $B$ on warming while ' $D$ ' can produce gas ' $B$ ' on reaction with dilute $H _{2} SO _{4}$ at room temperature. ' $A$ ' imparts a deep golden yellow colour to a smokeless flame on Bunsen burner. Identify 'A', $' B$ ', ' $C$ ' and ' $D$ ' respectively are

The factor of $\Delta G$ values is important in metallurgy. The $\Delta G$ values for the following reactions at $800^{\circ} C$ are given as $ S _{2}(g)+2 O _{2}(g) \longrightarrow 2 SO _{2}(g) ; \Delta G=-544 \,kJ$ $2 Zn (s)+ S _{2}(g) \longrightarrow 2 ZnS (s) ; \Delta G=-293 \,kJ $ $2 Zn (s)+ O _{2}(g) \longrightarrow 2 ZnO (s) ; \Delta G=-480\, kJ$ The $\Delta G$ for the reaction, $2 ZnS (g)+3 O _{2}(g) \longrightarrow 2 ZnO (g)+2 SO _{2}(g)$ will be

$KO _{2}$ (potassium superoxide) is used in oxygen cylinders in space and submarines because of it

Siderite is mainly ore of

Which of the following statements is not correct for a nucleophile ?

Which one of the following is not an isomer of $3-methylbut-1-yne$?

Magnetic moment 2.84 B.M. is given by (At. nos, Ni=28, Ti=22, Cr=24, Co=27)

Gadolinium belongs to 4f series. It's atomic number is 64. Which of the following is the correct electronic configuration of gadolinium ?

Cryolite is

The metallic lustre exhibited by sodium is due to

Arrange the following compounds in the increasing order of their acidic strength i. $m$-nitrophenol ii. $m$-cresol iii. phenol iv. $m$-chlorophenol

The total number of optical isomers possible for 2,3-dibromobutane is

Photochemical smog always contains

Which among the following is an electron deficient compound?

If $Cu^{2+}$ ions is treated with excess of $KCN$, the complex formed is

Which of the following do not have tetrahedral geometry?

Property of the alkaline earth metals that increases with their atomic number is

Molar heat of vaporisation of a liquid is $6 \,kJ\, mol^{-1}$. If the entropy change is $16 \,J \,mol^{-1}\, K^{-1}$, the boiling point of the liquid is

A compound $A$ has a molecular formula $C_2Cl_3OH$. It reduces Fehling's solution and on oxidation, gives a monocarboxylic acid $B$. $A$ can be obtained by the action of chlorine on ethyl alcohol. $A$ is

The reaction of a primary amine with chloroform and ethanolic solution of $KOH$ is called

Which of the following pairs has the same size?

Which of the following chemicals does not liberate hydrogen gas on reaction with aluminium metal?