To determine which of the given solutions would have a pH greater than 7.00, we need to consider the nature of each compound (whether it forms acidic, basic, or neutral solutions when dissolved in water).
1. [tex]$NH_4Br$[/tex]:
- [tex]$NH_4^+$[/tex] (ammonium ion) is a weak acid.
- [tex]$Br^-$[/tex] (bromide ion) is a neutral ion because it comes from the strong acid HBr.
- Hence, [tex]$NH_4Br$[/tex] in water will produce a slightly acidic solution, and the pH will be less than 7.
2. [tex]$C_6H_5NH_3Br$[/tex] (aniline hydrobromide):
- [tex]$C_6H_5NH_3^+$[/tex] (anilinium ion) is a weak acid.
- [tex]$Br^-$[/tex] is neutral.
- This will also result in a slightly acidic solution, and the pH will be less than 7.
3. [tex]$Ca(NO_3)_2$[/tex] (calcium nitrate):
- Both [tex]$Ca^{2+}$[/tex] and [tex]$NO_3^-$[/tex] are neutral ions (since [tex]$NO_3^-$[/tex] comes from a strong acid [tex]$HNO_3$[/tex] and [tex]$Ca^{2+}$[/tex] does not affect pH).
- Therefore, [tex]$Ca(NO_3)_2$[/tex] results in a neutral solution with a pH around 7.
4. [tex]$C_6H_5COONa$[/tex] (sodium benzoate):
- [tex]$C_6H_5COO^-$[/tex] (benzoate ion) is the conjugate base of benzoic acid, which is a weak acid.
- [tex]$Na^+$[/tex] is a neutral ion.
- The benzoate ion will hydrolyze in water to produce [tex]$OH^-$[/tex] ions, making the solution basic.
- Hence, [tex]$C_6H_5COONa$[/tex] will have a pH greater than 7.
Based on this analysis, the compound that would be expected to have a pH greater than 7.00 is:
D. [tex]$C_6H_5COONa$[/tex].
