Question

Rita added dilute hydrochloric acid to four metals. She recorded her observations in the table given below. While noting her observations she made some errors. 

 

• A. 1 only
• B. 3 only
• C. Both 1 and 4
• D. Both 2 and 4

Hint:

The "gas given off" in these reactions is Hydrogen ((H_2)), which can be tested using a burning splinter; it extinguished with a characteristic 'pop' sound!

Answer 1

The Correct Option is D

To determine which observations made by Rita are correct, we need to recall the reactivity of metals with dilute hydrochloric acid (HCl). Generally, when metals react with HCl, hydrogen gas is released, and a salt is formed.

The general reaction for metals with hydrochloric acid is:

\(\text{Metal} + \text{HCl} \rightarrow \text{Metal Chloride} + \text{H}_2 \uparrow\)

Let's examine each metal:

1. Copper: Copper does not react with dilute hydrochloric acid because it is less reactive than hydrogen. Therefore, no gas would be given off.
2. Iron: Iron reacts with dilute hydrochloric acid to produce iron(II) chloride and hydrogen gas. Thus, a gas should be given off.
3. Magnesium: Magnesium is highly reactive and would react vigorously with dilute hydrochloric acid to produce magnesium chloride and hydrogen gas. Therefore, gas should be given off.
4. Zinc: Zinc reacts with dilute hydrochloric acid to form zinc chloride and hydrogen gas. Therefore, gas would be given off.

Based on this analysis, the correct observations should be:

• Copper: No gas given off
• Iron: Gas is given off
• Magnesium: Gas is given off
• Zinc: Gas is given off

Therefore, Rita made errors in her observations regarding copper and magnesium. The correct choices according to the observations would be options 2 and 4.

Hence, the correct answer is:

Both 2 and 4