Please help me with this Chemistry question!

What type of reaction is shown below? check all that apply. 2h2o2 → 2h2o + o2 synthesis decomposition combustion

If you add 5.00 ml of 0.100 m sodium hydroxide to 50.0 ml of acetate buffer that is 0.100 m in both acetic acid and sodium acetate, what is the ph of the resulting solution? acetic acid: ka = 1.8. x 10-5

If i add water to oil what will happen