How many moles of NaOH need to be added to 200.0 mL of a 0.200 M solution of HF to make a buffer with a pH of 3.50? (Ka for HF is 6.8 × 10⁻⁴)

You have 1.5 liter of solution that is composed of 8.88 grams of NH3 and 11.33 grams of ammonium chloride mixed well. Kb for ammonia =1.8 x 10^-5 (A) is this a buffer solution? Why or why not? (B)if it is a buffer solution, what is the pH of this buffer solution? (C)how many mL of 1.50 M HCl can be added to this solution before the buffer is exhausted (d) how many mL of 1.5 M NaOH can be added to this solution before the buffer is exhausted?

You need to prepare a pH = 9.20 buffer solution containing NH3 and NH4Cl. If you start with 0.71 M NH4Cl solution, what concentration of NH3 l will you need to also start with? (Kb for NH3 is 1.8x10-5)

Calculate the pH of a buffer solution containing 0.584 mol HA weak acid and 0.703 mol A- in 130.1 mL  after 0.158 g of NaOH was added? [Ka= 1.56 ×10-5] Report your answer with three decimals. Enter numbers only; do not enter units.