Indicate whether each of the following compounds will give an acidic, basic or neutral solution when dissolved in water. Clear All ammonium bromide potassium hypochlorite calcium perchlorate ammonium nitrate The pH will be less than 7. The pH will be approximately equal to 7. The pH will be greater than 7. Submit AnswerRetry Entire Group

1. - pH < 7

2. - pH > 7

3. - pH approximately 7

4. - pH < 7

Explanation:

To answer this question we should think in terms of finding in each salt the acid and base from which it came from, and determining for the the cation and/or anion, the possible hydrolization hydrolization reactions.

1.-ammonium bromide, NH₄Br, salt forms from the neutralization reaction:

NH₃ + HBr ⇒ NH₄⁺ + Br ⁻

weak base strong Acid weak conjugate very weak conjugate

acid of weak base NH₃ base of strong acid HBr

Ka = 5.6 x 10⁻¹⁰

Thus the pH will be determined by NH₄⁺ and the pH < 7

2.-potassium hypochlorite, KClO:

KOH + HClO ⇒ ClO⁻ + H₂O + K⁺

Strong base weak acid conjugate base of neutral neutral

of weak acid HClO

Here the pH will be driven by the conjugate base ClO⁻ since water is neutral. Therefore pH > 7

3. - calcium perchlorate, Ca (ClO₄) ₂:

Ca (OH) ₂ + HClO₄ ⇒ ClO₄⁻ + H₂O + Ca²⁺

strong base strong acid very weak conjugate neutral neutral

base

Here the conjugate base coming from the strong acid HClO₄ will be a very weak one for all practical purposes. The pH will be approximately 7 since it will not hydrolize to any appreciable extent.

4. - ammonium nitrate, NH₄NO₃:

HNO₃ + NH₃ ⇒ NH₄⁺ + NO₃⁻

very strong weak base weak conjugate very weak conjugate

acid acid base

Ka = 5.6 x 10⁻¹⁰

Here the pH will be dominated by the conjugate acid NH₄⁺ since NO₃⁻ is a very weak base. Thus its pH will be less than 7