Baljinder Kaur Solutions for Chapter: Physical and Chemical Changes, Exercise 4: Mind Tilling

Take a piece of sodium and drop it in water. You will see that sodium melts to form a silvery globule and darts on the surface of the water. Part of sodium vapourises and burns along with hydrogen gas giving a golden yellow flame.

$2\mathrm{Na}+2{\mathrm{H}}_2\mathrm{O}\to 2\mathrm{NaOH}+{\mathrm{H}}_2\uparrow$

Now answer the following question:

Solution becomes _____ to touch.

Take a piece of sodium and drop it in water. You will see that sodium melts to form a silvery globule and darts on the surface of the water. Part of sodium vapourises and burns along with hydrogen gas giving a golden yellow flame.

$2\mathrm{Na}+2{\mathrm{H}}_2\mathrm{O}\to 2\mathrm{NaOH}+{\mathrm{H}}_2\uparrow$

Now answer the following question:

The beaker becomes hot because of _____ reaction.

Take a piece of sodium and drop it in water. You will see that sodium melts to form a silvery globule and darts on the surface of the water. Part of sodium vapourises and burns along with hydrogen gas giving a golden yellow flame.

$2\mathrm{Na}+2{\mathrm{H}}_2\mathrm{O}\to 2\mathrm{NaOH}+{\mathrm{H}}_2\uparrow$

Now answer the following question:

The change is _____ because the products formed can't be reversed.