Question

The condition necessary for a chemical reaction is written on:

• A. Top of the arrow
• B. Top of the plus sign
• C. Below the arrow
• D. Both A and C

Answer 1

The correct option is D

Both A and C

The explanation for the correct option

D. Both A and C

• Some chemical reaction requires conditions like use of catalyst, temperature,pressure etc.
• These conditions are written top and below the arrow.
• For example,

$\underset{\mathrm{Nitrogen}}{{\mathrm{N}}_2\left(\mathrm{g}\right)}+\underset{\mathrm{Hydrogen}}{3{\mathrm{H}}_2\left(\mathrm{g}\right)}\underset{\mathrm{Pt}\left(\mathrm{platinum}\right)}{\overset{240\mathrm{atm}\mathrm{pressure}}{\to }}\underset{\mathrm{Ammonia}}{2{\mathrm{NH}}_3\left(\mathrm{g}\right)}$

A. Top of the arrow

• If there is only one condition for chemical reaction, it is written above the arrow.
• For example, $\underset{\mathrm{Ferrous}\mathrm{Sulphate}}{{\mathrm{FeSO}}_4\left(\mathrm{s}\right)}\stackrel{\mathrm{Heat}}{\to }\underset{\mathrm{Ferric}\mathrm{oxide}}{{\mathrm{Fe}}_2{\mathrm{O}}_3\left(\mathrm{s}\right)}+\underset{\mathrm{Sulphur}\mathrm{dioxide}}{{\mathrm{SO}}_2\left(\mathrm{g}\right)}+\underset{\mathrm{Sulphur}\mathrm{trioxide}}{{\mathrm{SO}}_3\left(\mathrm{g}\right)}$

C. Below the arrow

• If there are two condition for chemical reaction, then one condition is written above the arrow and other is written below the arrow.

The explanation for the incorrect option

B. Top of the plus sign

• Nothing is written on top of plus sign.

Hence option (D) is correct, condition necessary for a chemical reaction is written on both top and below the arrow.