List of top Chemistry Questions

Formation of $ClF_3$ from $Cl_2$ and $F_2$ is an exothermic process. The equilibrium system can be represented as $ {Cl2_{(g)} +3F2_{(g)}<=>2ClF3}$ ; $\Delta H=-329\,kj\,mol^{-1}$ Which of the following will increase quantity of $ClF_3$ in the equilibrium mixture?

How many gram equivalents of NaOH are required to neutralize 25 $cm^3$ of decinormal HCl solution ?

If $K_{sp}$ of $Mg(OH)_2$ is $1.2 ? 10^{-11}$. Then the highest pH of the $0.1\, M$ solution of $Mg^{2+}$ ion from which $Mg(OH)_2$ is not precipitated is

If pH of a solution decreases from 5 to 2, then it is

If $S_1, S_2, S_3$ and $S_4$ are the solubilities of $AgCl$ in water, in $0.01\, M\, CaCl_2$, in $0.01\, M\, NaCl$ and in $0.05\, M\, AgNO_3$ respectively at a certain temperature, the correct order of solubilities is

If the solubility of $Ag_2CrO_4$ is S mole/litre.Then its solubility product is

In a vessel $N_2$, $H_2$ and $NH_3$ are at equilibrium. Some helium gas is introduced into the vessel so that total pressure increases while temperature and volume remain constant. According to Le Chatelier's principle, the dissociation of $NH_3$

In an experiment, $NO_2$ gas is prepared and taken into $3$ test tubes $X$, $Y$ and $Z$. $NO_2$ gas which is brown in colour dimerises into $N_2O_4$ which is colourless. Test tube $X$ is kept at room temperature, $Y$ is kept in ice and $Z$ is kept in hot water. What colour changes will you observe in the test tubes and why? $\underset{\text{Brown}}{ {2NO2_{(g)} <=> }}$ $\underset{\text{Colourless}}{ {N2O4_{(g)}}}$ ; $\Delta H=-57.2\,kJ\,mol^{-1}$

In the lime kiln, the reversible reaction $ {CaCO3 <=> CaO +CO2}$ proceeds to completion because of

In the relation, $K_p = K_c (RT)^{\Delta n}$ the value of $\Delta n$ is

$K_a$ for $CH_3COOH$ is $1.8 \times 10^{-5}$ and $K_b$ for $NH_4OH$ is $1.8 \times 10^{-5}$. The $pH$ of ammonium acetate will be

$NH_4CN$ is a salt of weak acid $HCN (K_a = 6.2 \times 10^{-10})$ and a weak base $NH_4OH (K_b = 1.8 \times 10^{-5})$. A one molar solution of $NH_4CN$ will be

pH of $0.01 M (NH_4)_2 SO_4$ and $0.02 \,M\, NH_4OH $ buffer $(pK_a of NH^+_4 = 9.26)$ is

The expression for the solubility product of $Ag_2CO_3$ will be :

The theory of spontaneous generation stated that

The vapour density of $N_2O_4$ at a certain temperature is 30. What is the percentage dissociation of $N_2O_4$ at this temperature ?

Three sparingly soluble salts $M_2X, MX$ and $MX_3$ have same value of solubility product. Their solubilities follow the order

Vapour density of $PCl_5$ is $104.16$ but when heated to $230^{\circ} C$ its vapour density is reduced to 62. The degree of dissociation of $PCl_5$ at this temperature will be

Water is a

What is $K_c$ for the following equilibrium when equilibrium concentration of each substance is $[SO_2] = 0.60 M, [O_2] = 0.82 M$ and $ [SO_3] = 1.90 M?$ $\hspace10mm 2SO_2 (g)+O_2(g) \rightleftharpoons 2SO_3 (g) $

What is $pOH$ of an aqueous solution with hydrogen ion concentration equal to $3 \times 10^{-5}\,mol\, L^{-1}$?

What will be the pH of $1\times 10^{-4}\,M \,H_2SO_4$ solution?

When ethanol and acetic acid are mixed together in equimolar proportions, equilibrium is attained when 2/3rd of acid and alcohol are consumed. The equilibrium constant for the reaction is

When hydrochloric acid is added to cobalt nitrate solution at room temperature, the following reaction takes place and the reaction mixture becomes blue. On cooling the mixture, it becomes pink. On the basis of this information mark the correct answer. $\underset{\text{Pink}}{ {[Co(H2O)6]^{3+}}_{(aq)}}$ $+$ $ {4Cl^{-}_{(aq)}<=>}$ $\underset{\text{Blue}}{ {[CoCl4]}^{2-}_{(aq)}}$$ {+ 6H2O_{(l)}}$

When sulphur is heated at $900\,K$, $S_8$ is converted to $S_2$. What will be the equilibrium constant for the reaction if initial pressure of $1\,atm$ falls by $25\%$ at equilibrium?