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

Step 1: Understanding Metal-Acid Reactivity: 
Metals that are more reactive than hydrogen (positioned above hydrogen in the reactivity series) displace hydrogen from dilute acids to produce hydrogen gas. 

Step 2: Evaluating the Observations: 
beginenumerate Copper (Cu): Below hydrogen in the reactivity series. It does not react with dilute HCl. (Observation 1 is Incorrect). Iron (Fe): Above hydrogen. It reacts to give (H_2) gas. (Observation 2 is Correct). Magnesium (Mg): Highly reactive, above hydrogen. It reacts vigorously to give (H_2) gas. (Observation 3 is Incorrect). Zinc (Zn): Above hydrogen. It reacts to give (H_2) gas. (Observation 4 is Correct). endenumerate 

Step 3: Identifying Correct Observations: 
Only observations 2 (Iron) and 4 (Zinc) accurately reflect the chemical reality. 

Step 4: Final Answer: 
The correct choice is Both 2 and 4.