This dissociation occur because:
O had to bond with H due to the Hydrogen bonding rule, which will form OH~ (Hydroxide).
K is more attracted to Hydroxide than Cl, so it will depart Cl and bond with OH~.
that leaves a H and a Cl, which one has a positive charge and the other has a negative, so they will bond and form Hydrochloric Acid.
Number of atoms : 1.26 x 10²³
<h3>Further explanation </h3>The mole is the number of particles(molecules, atoms, ions) contained in a substance
1 mol = 6.02.10²³ particles
Can be formulated
N=n x No
N = number of particles
n = mol
No = Avogadro's = 6.02.10²³
0.21 moles of Al, so n = 0.21
Number of atoms :