Predict whether aqueous solutions of the following compounds...

Predict whether aqueous solutions of the following compounds are acidic, basic, or neutral: $(\mathbf{a})\mathrm{NH}_{4} \mathrm{Br},(\mathbf{b}) \mathrm{FeCl}_{3}$ $(\mathbf{c}) \mathrm{Na}_{2} \mathrm{CO}_{3},(\mathbf{d}) \mathrm{KClO}_{4},(\mathbf{e}) \mathrm{NaHC}_{2} \mathrm{O}_{4}$

Key Concepts

Hydrolysis of Metal Ions

Hydrolysis of metal ions involves the interaction of metal cations with water, which can lead to the release of hydrogen ions into the solution. This is especially notable for small, highly charged metal ions, which can cause the solution to become acidic.

Strength of Acids and Bases

The inherent strength of the parent acid or base from which the salt is derived is crucial in predicting the pH of the solution. Salts from a strong acid and a weak base will typically result in an acidic solution, while those from a weak acid and a strong base will usually produce a basic solution.

Ionic Dissociation in Water

Ionic dissociation is the process by which ionic compounds separate into their constituent ions when dissolved in water. The nature of these ions—whether they are neutral, acidic, or basic—affects the overall pH of the solution.

Conjugate Acid-Base Pairs

Conjugate acid-base pairs are formed when an acid donates a proton to form its conjugate base, or a base accepts a proton to form its conjugate acid. The strength of these conjugate pairs plays a significant role in determining the direction and extent of the hydrolysis reactions in salt solutions.

Salt Hydrolysis

Salt hydrolysis refers to the reaction between the ions that make up a salt and water, which can result in the production of H+ or OH– ions. This process determines whether the resulting solution will be acidic, basic, or neutral based on the nature of the ions involved.

Transcript

00:01 In this question, we have to determine the nature of the compound, acidic, or basic, or either it's neutral.

00:10 So, starting with compound number one, we have nh4br, ammonium bromide.

00:18 So, writing the equation, nh4, br.

00:29 So writing the dissociation, we see that there are two products, ammonia, nh4, nh4 positive, plus br negative.

00:49 Yes, br negative.

00:52 Here, br negative anion is the conjugate base of strong acid, which is hbr.

00:59 It will not affect the ph.

01:02 We have a cation, nh4 positive, weak base, a conjugate acid of a weak base, which will decrease the ph.

01:14 So option a, we have an acidic solution.

01:29 Option number two, the compound given is ferricloride fecl3.

01:37 So we have f .e .c .l .3, which gives me fecl3.

02:02 So on the dissociation of facl3, we have two products.

02:07 One is f .e .3 positive.

02:12 And another one is three moles of chlorine negative.

02:21 F .e.

02:22 Positive is f .e.

02:25 3 positive is the conjugate acid of weak base that will decrease the ph, while chlorine negative is the conjugate base of strong acid, which will not affect the ph.

02:38 So this will be also the same...

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