What is the pH of an aqueous solution obtained by mixing 6 gram of acetic acid and 8.2 gram of sodium acetate and making the volume equal to 500ml. (Given: K_a for acetic acid is 1.8 times 10^-5)

What is the pH of an aqueous solution obtained by mixing 6 gram of ace

1.	What is the pH of an aqueous solution obtained by mixing 6 gram of acetic acid and 8.2 gram of sodium acetate and making the volume equal to 500ml. (Given: K_a for acetic acid is 1.8 times 10^-5)
Answer» Solution :ACCORDING to Henderson- Hessalbalch equation, `pH=pK_a+log (["salt"])/(["acid"])` Given that `K_a=1.8 times 10^-5` `therefore pK_a=-log K_a=-log(1.8 times 10^-5)=4.74` `["Salt"]=( "Number of moles of sodium acetate")/( "Volume of the solution (LITRE)")` Number of moles of sodium acetate= `("mass of sodium acetate")/("molar mass of sodium acetate")=8.2/8.2=0.1` `therefore["Salt"]=(0.1 MOLE)/(1/2 litre)=0.2M` `["acid"]=(("mass of" CH_3COOH//"Molar mass of" CH_3COOH))/("volume of solution in litre"))=((6//60))/12=0.2M` `therefore pH=4.74+log ((0.2))/((0.2))` `pH=4.74+log 1` `pH=4.74+0=4.74`