Question

Which equation shows a physical change?
A.Pb(NO3)2 (aq) + 2KI(aq) → 2KNO3(aq) + PbI2(s)
B. HCl(aq) + NaOH(aq) → NaCl(aq) + H2O(l)
C.2H2O(l) → 2H2(g) + O2(g)
D.H2O(g) → H2O(s)

Answer 1

Answer:

The correct option is D

Explanation:

A physical change is a change in which no new substance is formed and can be easily reversible.

Of the options provided, option D is correct because gaseous water (steam) can be converted to solid water (ice) through freezing and can be reversed by heating up the solid water. Thus, this process does not involve the formation of any new substance.

Note that the processes of freezing and heating described must pass through the liquid phase.