State reasons for the following:
$(i)$ Metals are good conductors of heat.
$(ii)$ Addition of some silver to pure gold for making ornaments.
$(iii)$ Inability of non-metals to displace hydrogen from dilute sulphuric acid.

(N/A) $(i)$ When a metal is heated,its atoms gain energy and vibrate more vigorously. This energy is transferred to the free electrons,which move through the metal lattice. These electrons transfer their kinetic energy to other atoms and electrons throughout the structure,making metals good conductors of heat.
$(ii)$ Pure gold,known as $24$ carat gold,is extremely soft and malleable. It is not suitable for making jewellery as it would easily deform. Therefore,a small amount of silver or copper is added to create an alloy,which makes the gold harder and more durable.
$(iii)$ Non-metals are electronegative and act as electron acceptors. To displace hydrogen from dilute acids,a substance must be able to donate electrons to $H^{+}$ ions to form $H_2$ gas. Since non-metals cannot provide electrons,they are unable to displace hydrogen from dilute sulphuric acid.