List of top Chemistry Questions

Amongst \( \text{Ni(CO)}_4 \), \( [\text{Ni(CN)}_4]^{2-} \), and \( [\text{NiCl}_4]^{2-} \), which is paramagnetic?

The freezing point of a solution composed of 10.0 g of KCl in 100 g of water is 4.5°C. Calculate the van't Hoff factor, \(i\), for this solution.

Which of the following is the correct comparison of the stability of the molecules?

Heat of formation, \( \Delta H_f \), of an explosive compound like NC\( _3 \) is:

For the reaction, \[ C_3H_8(g) + 5O_2(g) \rightarrow 3CO_2(g) + 4H_2O(l) \] at constant temperature, \( \Delta H = \Delta E \) is:

The favourable conditions for a spontaneous reaction are:

For the reaction \( 2A + B \rightleftharpoons C \), \( \Delta H = x \) cal, which one of the following conditions would favour the yield of C on the basis of Le-Chatelier's principle?

Compound A and B are treated with dil. HCl separately. The gases liberated are Y and Z respectively. Y turns acidified dichromate paper green while Z turns lead acetate paper black. The compound A and B are respectively:

The EMF of the cell, \[ \text{Mg}^{2+}(0.01M) \parallel \text{Sn}^{2+}(0.1M) \parallel \text{Sn at 298K} \] is:

Consider the following equation, which represents the reaction in the extraction of chromium from its ore: \[ \text{Fe}_2\text{O}_3 + 4\text{Na}_2\text{Cr}_2\text{O}_7 + 3O_2 \rightarrow 2\text{Fe}_2\text{O}_3 + 4\text{Na}_2\text{CrO}_4 + 3O_2 \] Which of the following statements about the oxidation states of the substances is correct?

A vessel at 1000 K contains CO\(_2\) with a pressure of 0.5 atm. Some of the CO\(_2\) is converted into CO on the addition of graphite. The value of K if the total pressure at equilibrium is 0.8 atm, is:

In the reversible reaction, \[ 2NO_2 \rightleftharpoons \text{N}_2\text{O}_4 \] the rate of disappearance of \( NO_2 \) is equal to:

A chemical reaction was carried out at 300 K and 280 K. The rate constants were found to be \( k_1 \) and \( k_2 \) respectively. Then

The rate constant of a reaction at temperature 200 K is 10 times less than the rate constant at 400 K. What is the activation energy of the reaction?

The radio-isotope used for treatment of thyroid disorders is:

Two glass bulbs A and B are connected by a very small tube having a stop-cock. Bulb A has a volume of 100 cm\(^3\) and contained the gas while bulb B was empty. On opening the stop-cock, the pressure fell down to 40%. The volume of the bulb B must be:

20 mL of 2.0 M NaOH is added to 50 mL of 0.2 M HCl. The pH of this solution after mixing is:

A crystalline solid:

Tetragonal crystal system has the following unit cell dimensions:

"925 fine silver" means an alloy of:

"925 fine silver" means an alloy of:

Self condensation of two moles of ethyl acetate in the presence of sodium ethoxide after acidification yields:

Which one of the following will be most basic?

MnO\(_2\) dissolves in water to give an acid. The color of the acid is:

\( \text{C}_6\text{H}_4\text{Br} \) undergoes Wurtz reaction. We may expect some of the following products: