How did Ballistics solve the St. Valentine’s case?

Given the table below, what is the chemical formula for a compound between rb and the nitrate ion no3 -1? nitrate ion no3 -1 phosphate po4 -3 sulfate so4 -2 acetate c2h3o2 -1 ammonium nh4 +1 chromate cro4 -2 carbonate co3 -2 dichromate cr2o7 -2 permanganate mno4 -1 sulfite so3 -2 rbno3 rb2no3 rb(no3)2 rb2(no3)3

Calculate the molarity of each of the following solutions. part a) 0.12 mol of lino3 in 5.5 l of solution part b) 60.7 g c2h6o in 2.48 l of solution part c) 14.2 mg ki in 100 ml of solution

What is the ph of a solution that has a hydrogen ion concentration of 1.0 * 10 -9 m?