List of top Chemistry Questions

Choose the correct statement from the following which is related to electrochemical series

Which one of the following is correct decreasing order of acidity?

In a Galvanic cell

$23\, g$ of ethanol $(C_2H_5OH)$ on reaction with ethanoic acid $(CH_3COOH)$ forms $44\, g$ of ethyl ethanoate $(CH_3COOC_2H_5)$ and some weight of water. The percentage yield of the reaction is

$ A(g)+3B(g)4C(g) $ Initially concentration of $ A $ is equal to that of $ B $ . The equilibrium concentrations of $ A $ and $ C $ are equal. $ {{K}_{c}} $ is:

The basicity of pyrophosphorous acid is

Among the following, which species represents a pseudohalide?

An alkene $ {{C}_{4}}{{H}_{8}} $ , was treated with ozone and then with zinc and water to give acetone and formaldehyde. The alkene is:

A sample of pure PCl₅ was introduced into an evacuated vessel at 473 K. After equilibrium was attained, concentration of PCl₅ was found to be \(0.5×10^{–1}\ mol L^{–1}\). If value of K_c is \(8.3×10^{–3}\), what are the concentrations of PCl₃ and Cl₂ at equilibrium?
\(PCl_5 (g) ⇋ PCl_3 (g) + Cl_2(g)\)

The time required for 10% completion of a first order reaction at 298 K is equal to that required for its 25% completion at 308 K. If the value of A is \(4 \times 10^{10} s^{-1}\) . Calculate \(k\) at 318 K and \(E_a\).

The oxidation number of cobalt in \(K[Co(CO)_4]\) is

The following data were obtained during the first order thermal decomposition of \(SO_2Cl_2\) at a constant volume.
\(SO_2Cl_2(g) → SO_2(g) + Cl_2(g)\)

Experiment	Time/s-1	Total pressure/atm
1	0	0.5
2	100	0.6

Calculate the rate of the reaction when total pressure is 0.65 atm.

Predict the products of electrolysis in each of the following: 
 (i) An aqueous solution of AgNO₃ with silver electrodes. 
 (ii) An aqueous solution of AgNO₃ with platinum electrodes. 
 (iii) A dilute solution of H₂SO₄ with platinum electrodes. 
 (iv) An aqueous solution of CuCl₂ with platinum electrodes.

Nitric oxide reacts with Br₂ and gives nitrosyl bromide as per reaction given below:
\(2NO (g) + Br_2 (g) ⇋ 2NOBr (g)\)
When 0.087 mol of NO and 0.0437 mol of Br₂ are mixed in a closed container at constant temperature, 0.0518 mol of NOBr is obtained at equilibrium. Calculate equilibrium amount of NO and Br₂ .

Reaction of diborane with ammonia gives initially

A binary solid has a primitive cubical structure with $B^-$ ions constituting the lattice points and $A^+$ ions occupying $25\%$ of its tetrahedral holes. The molecular formula of the crystal is

Among the following, the optically active compound is

Sphalerite is concentrated by

$1.5\, g$ of a non-volatile, non-electrolyte is dissolved in $50 \,g$ benzene $(K_b\, =\, 2.5\, K kg \,mol^{-1}$ ). The elevation of the boiling point of the solution is $0.75\, K$. The molecular weight of the solute in $g$ $mol^{-1}$ is

IUPAC name of $ C{{H}_{3}}CH=\underset{\begin{align} & | \\ & C{{H}_{2}} \\ & | \\ & C{{H}_{3}} \\ \end{align}}{\mathop{C}}\,C{{H}_{3}} $

An atom with high electronegativity has

Ammonium ion $\left( NH _{4}^{+}\right)$ reacts with nitrite ion $\left( NO _{2}^{-}\right)$ in aqueous solution according to the equation $NH _{4}^{+}(a q)+ NO _{2}^{-}(a q) \longrightarrow N _{2}(g)+2 H _{2} O (l)$ The following initial rates of reaction have been measured for the given reactant concentrations. Which of the following is the rate law for this reaction?

A gas mixture contains 50% helium and 50% methane by volume. What is the percent by weight of methane in the mixture ?

For the reaction $ 2{{N}_{2}}{{O}_{5}}(g)\xrightarrow[{}]{{}}4N{{O}_{2}}(g)+{{O}_{2}}(g) $ if the concentration of $ N{{O}_{2}} $ increases by $ 5.2\times {{10}^{-3}} $ M in 100 s then the rate of the reaction is:

Ammonia will not form complex with