Answered

Discover the answers to your questions at Westonci.ca, where experts share their knowledge and insights with you. Experience the convenience of getting reliable answers to your questions from a vast network of knowledgeable experts. Discover detailed answers to your questions from a wide network of experts on our comprehensive Q&A platform.

The table below lists some acids and bases.

\begin{tabular}{|l|l|l|l|}
\hline Strong acids & Weak acids & Weak bases & Strong bases \\
\hline HBr & [tex]$CH_3COOH$[/tex] & [tex]$NH_3$[/tex] & NaOH \\
\hline [tex]$HNO_3$[/tex] & HCOOH & [tex]$NH_4OH$[/tex] & KOH \\
\hline [tex]$H_2SO_4$[/tex] & & & [tex]$Ca(OH)_2$[/tex] \\
\hline
\end{tabular}

Which reaction yields a salt that has a [tex]$pH \ \textless \ 7$[/tex]?

A. [tex]$KOH + HBr$[/tex]
B. [tex]$HCOOH + KOH$[/tex]
C. [tex]$Ca(OH)_2 + H_2SO_4$[/tex]
D. [tex]$NH_3 + HNO_3$[/tex]

Sagot :

GinnyAnswer
To determine which reaction yields a salt with [tex]\( \text{pH} < 7 \)[/tex], we need to consider the properties of the acids and bases involved in each reaction. Specifically, we need to determine whether the acids or bases are strong or weak. The general rules for the pH of salts formed from acid-base reactions are as follows:

1. Strong acid + Strong base → Neutral salt (pH = 7)
2. Strong acid + Weak base → Acidic salt (pH < 7)
3. Weak acid + Strong base → Basic salt (pH > 7)
4. Weak acid + Weak base → Typically varies

Let's analyze each given reaction:

1. [tex]\( KOH + HBr \)[/tex]:
- [tex]\( KOH \)[/tex] is a strong base.
- [tex]\( HBr \)[/tex] is a strong acid.
- A reaction between a strong base and a strong acid will yield a neutral salt with [tex]\( \text{pH} = 7 \)[/tex].

2. [tex]\( HCOOH + KOH \)[/tex]:
- [tex]\( HCOOH \)[/tex] (formic acid) is a weak acid.
- [tex]\( KOH \)[/tex] is a strong base.
- A reaction between a weak acid and a strong base will yield a basic salt with [tex]\( \text{pH} > 7 \)[/tex].

3. [tex]\( Ca(OH)_2 + H_2SO_4 \)[/tex]:
- [tex]\( Ca(OH)_2 \)[/tex] is a strong base.
- [tex]\( H_2SO_4 \)[/tex] is a strong acid.
- A reaction between a strong base and a strong acid will yield a neutral salt with [tex]\( \text{pH} = 7 \)[/tex].

4. [tex]\( NH_3 + HNO_3 \)[/tex]:
- [tex]\( NH_3 \)[/tex] (ammonia) is a weak base.
- [tex]\( HNO_3 \)[/tex] is a strong acid.
- A reaction between a weak base and a strong acid will yield an acidic salt with [tex]\( \text{pH} < 7 \)[/tex].

Based on this analysis, the reaction that yields a salt with [tex]\( \text{pH} < 7 \)[/tex] is:

[tex]\( \boxed{4} \)[/tex] [tex]\( NH_3 + HNO_3 \)[/tex]
We hope our answers were helpful. Return anytime for more information and answers to any other questions you may have. Thank you for your visit. We're dedicated to helping you find the information you need, whenever you need it. Discover more at Westonci.ca. Return for the latest expert answers and updates on various topics.