Question

He 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?

A) KBr
B) HCOOK
C) CaSO4
D) NH4NO3

Answer 1

Answer : Option D)
`NH_(4)NO_(3)`

Explanation :

Amongst the given list of acids and bases, following are the strong acids and weak acids

Strong Acid: HBr,
`HNO_(3)` and
`H_(2)SO_(4)`

Weak Acid:
`CH_(3)COOH` and HCOOH

And strong bases with weak bases are given below;

Strong Base: NaOH, KOH and
`Ca(OH)_(2)`

Weak Base:
`NH_(4)OH` and
`NH_(3)`

Now, Acid + Base → Salt + Water

so, the salt of strong acid and weak base which will have pH < 7

will be
`NH_(4)NO_(3)`

because of the following acid base reaction (neutralization reaction)

`HNO_(3)` +
`NH_(4)OH` ↔
`NH_(4)NO_(3)` +
`H_(2)O`

Answer 2

The answer is D)NH4NO3