Solution (a) contains 0.01 m of nh4cl; solution
(b)contains 0.01 m of nacl; solution (c) contains 0.01 m of
naoh; andsolution (d) contains 0.01 m of ba(oh)2. arrange
the phof the solutions in an increasing order.

NH4Cl, NaCl, Ba(OH)2, NaOH

Explanation:

NH4Cl is an acidic salt formed by the neutralization of a strong acid (HCl) with a weak base (NH3). Hence, it will habe a PH<7 (the lowest PH).

NaCl is a neutral salt,formed by neutralization of a strong acid (HCl) with a strong base (NaOH). Hence, it will have a PH of 7.

Ba(OH)2 is a weak base. Therefore, it will have a PH between 8 and 10.

NaOh meanwhile, is a strong base. Therefore, it will have a PH between 10 to 13.

Hence, we have

NH4Cl < NaCl < Ba(OH)2 < NaOH

answer: the enthalpy of the overall chemical reaction is +87.88 kj or +88 kj.

according to hess's law, the overall enthalpy of a reaction is the difference between the sum of enthalpy values of all the products and the sum of enthalpy values of all the reactants.

δh(reaction) = ∑nδh(products) - ∑nδh(reactants)

δh(reaction) = [δh +δh] - [δh]

δh(reaction) = [1(-287.02) + 1(0) ] - [1(-374.9)] kj = +87.88 kj

here, δh (pcl3) = -287.02 kj, δh(cl2) = 0, δh(pcl5) = -374.9 kj

therefore, enthalpy of the overall reaction is +87.88 kj or +88 kj.