1. Balance the following equations: \[ \begin{array}{l} { }_{-} \mathrm{Na}_{3} \mathrm{PO}_{4}+\ldots \mathrm{HCl} ightarrow{ }^{+} \mathrm{NaCl}+{ }^{\mathrm{H}_{3} \mathrm{PO}_{4}} \\ \text { _ As + _ } \mathrm{NaOH} ightarrow \ldots \mathrm{Na}_{3} \mathrm{AsO}_{3}+\ldots \mathrm{H}_{2} \\ \mathrm{C}_{2} \mathrm{H}_{6}+\ldots \mathrm{O}_{2} ightarrow \ldots \mathrm{CO}_{2}+\ldots \mathrm{H}_{2} \mathrm{O} \\ { }_{-} \mathrm{NaOH}+\ldots \mathrm{H}_{2} \mathrm{SO}_{4} ightarrow \mathrm{Na}_{2} \mathrm{SO}_{4}+\mathrm{H}_{2} \mathrm{O} \\ \end{array} \] 2. What is the Benzo[a]pyrene (BaP) concentration in g/m3 for each of the following cases? a) 5ppb of BaP in a soil having a density of 3g/cm3 b) 10ppb of BaP in a water sample c) 500ppb of BaP in the air 3. If 60 grams of acetic acid (HAc=CH3COOH) is added to enough distilled water to make 1 liter of solution, calculate the followings for the equilibrium conditions (Ka=1.75105) : i) acetate ion (Ac=CH3COO) concentration ii) pH of the solution iii) dissociation efficiency in \% 4. Carbonic acid (H2CO3) has 2 -step dissociation in the water as the following reactions. If 6.2 grams of H2CO3 is added in to 1L of water, calculate the pH values during the 1st and 2nd dissociation equilibrium and in total (overall pH ). 1st step: H2CO3H++HCO3 Ka1=4.45107 2nd step: HCO3+H++CO32Ka2=4.691011