this is the only one i don’t know

Can someone me with questions 12 and 13 plz.

Which buffer would be better able to hold a steady ph on the addition of strong acid, buffer 1 or buffer 2? explain. buffer 1: a solution containing 0.10 m nh4cl and 1 m nh3. buffer 2: a solution containing 1 m nh4cl and 0.10 m nh3

Consider the four elements above. which one of these elements will combine with oxygen in a 1: 1 ratio?