Corrosion of silver is due to the formation of

A metal compound A reacts with dilute hydrochloric acid to produce effervescence. The gas evolved extinguishes a burning candle.

Write a balanced equation for the reaction if one of the compounds formed is calcium chloride.

Choose the method of preparation of Iron (II) sulphate, from the methods given in the list:

[List: A. Neutralization B.Precipitation C.Direct combination D.Substitution]

Which of the following are combination reaction?

(i) $2{\mathrm{KClO}}_3\stackrel{∆}{\to }2\mathrm{KCl}+3{\mathrm{O}}_2$

(ii) $\mathrm{MgO}+{\mathrm{H}}_2\mathrm{O}\to \mathrm{Mg}{\left(\mathrm{OH}\right)}_2$

(iii) $4\mathrm{Al}+3{\mathrm{O}}_2\to 2{\mathrm{Al}}_2{\mathrm{O}}_3$

(iv) $\mathrm{Zn} + {\mathrm{FeSO}}_4\to {\mathrm{ZnSO}}_4 + \mathrm{Fe}$

Choose the method of preparation of Iron (III) chloride, from the methods given in the list:

[List: A. Neutralization B.Precipitation C.Direct combination D.Substitution]

Consider the following equation of the chemical reaction of a metal M

$4\mathrm{M}+3{\mathrm{O}}_2 \stackrel{}{\to } {\mathrm{M}}_2{\mathrm{O}}_3$

The equation represents:- 

Which of the following is a reversible reaction?

$$\begin{gathered} \mathrm{A}: \mathrm{NaCl}\left(\mathrm{aq}\right) + {\mathrm{AgNO}}_3\left(\mathrm{aq}\right) \to {\mathrm{NaNO}}_3\left(\mathrm{aq}\right) + \mathrm{AgCl}\left(\mathrm{s}\right) \\ \mathrm{B}: {\mathrm{NH}}_4\mathrm{Cl}\left(\mathrm{s}\right) \rightleftharpoons {\mathrm{NH}}_3\left(\mathrm{g}\right) + \mathrm{HCl}\left(\mathrm{g}\right) \end{gathered}$$

${\mathrm{CH}}_4+{\mathrm{Cl}}_2 \stackrel{\mathrm{sunlight}}{\to } {\mathrm{CH}}_3\mathrm{Cl} + \mathrm{HCl}$

This reaction is 

Match the items of the column -I with column-II and choose the correct option.

Calcium oxide reacts vigorously with water to produce slaked lime.

${\mathrm{CaO}}_{\left(\mathrm{s}\right)}+{\mathrm{H}}_2{\mathrm{O}}_{\left(\mathrm{l}\right)} \to \mathrm{Ca}{\left(\mathrm{OH}\right)}_{2\left(\mathrm{aq}\right)}$

This reaction can be classified as:

(A) Combination reaction        (B) Exothermic reaction

(C) Endothermic reaction        (D) Oxidation reaction

Which of the following is the correct answer?