Response:
a)
, b) 
Clarification:
a) The absolute pressure at a depth of 27.5 meters is:



b) The force applied by the water is:



<span>Response:
Chlorine has 17 electrons, thus, for 1+ and 2+ ions, we require elements with 18 and 19 electrons, which are argon and potassium: Ar+ and K 2+.
For 1- and 2- ions, we need elements with 16 and 15 electrons, namely sulfur and phosphorus, represented as S- and P 2-.
It’s important to note that + ions indicate electron loss, while - ions reflect electron gain.</span>