If 8.7 g of butanoic acid, c4h8o2, is dissolved in enough water to make 1.0 l of solution, what is the resulting ph? a table with ka values can be found here.

Hello! Such questions are answered by using concept from chemical equilibrium and pH formulas. First, you are required to find the concentration of H+ or H3O+ ions at concentration by using chemical equilibrium secondly you will calculate pH for particular H+ concentration by using -log [H+] formula. Below the equation shows the reaction of butanoic acid with water producing butyrate and hydronium ions. Initially when the reaction is at time = 0 no H3O+ is produced, then, reaction starts and equilibrium is attained at which unknown (x) amount of H3O+ is formed. This unknown concentration is calculated as shown below (i don't know much maths so, i use online calculator). When concetration of H3O+ is in hand then you can simply calculate pH.

Also, before starting the calculation you should find out Molarity of given acid by following method,

Molarity = moles ÷ dm³
Molarity = (mass ÷ M. Mass) ÷ dm³
M. Mass of Butyric acid = 88 g/mol
So, Molarity = (8.7 g ÷ 88 g/mol) ÷ 1 dm³
Molarity = 0.0988 mol/dm³