The table below lists some acids and bases. strong acids weak acids weak bases strong bases hbr ch3cooh nh3 naoh hno3 hcooh nh4oh koh h2so4 ca(oh)2 which salt has a ph < 7?

Among the list of acids and bases, following are strong acid and base

Strong Acid: HBr, HNO3 and H2SO4

Weak Acid: CH3COOH and HCOOH

Strong Base: NaOH, KOH and Ca(OH)2

Weak Base: NH4OH, NH3

Now, we know that: Acid  + Base    →    Salt   + Water

Salt of strong acid and weak base will have pH < 7

Example:
1)  HBr    +           NH4OH    ↔       NH4Br     +     H2O
2) HNO3     +       NH4OH    ↔     NH4NO3    +    H2O
3) H2SO4    +     2 NH4OH  ↔     (NH4)2SO4  +  2 H2O 

Where are the following questions