Question

what is the balanced chemical reaction occurring when zinc metal is added to hydrofluoric acid? partial activity series k ca mg al zn fe ni pb h cu ag f₂ cl₂ br₂ i₂ no reaction occurs. zn + hf → znh + f zn + 2hf → znf₂ + h₂ zn + hf → znf + h

Explanation:

Step1: Check Activity Series

In the activity series, Zn is above H, so Zn can displace H from an acid (HF here). So a reaction occurs, eliminating "No reaction occurs."

Step2: Analyze Reaction Type

This is a single - displacement reaction: \( \text{Metal}+\text{Acid}
ightarrow\text{Metal Salt}+\text{Hydrogen Gas} \).

Step3: Analyze Each Option

• Option \( \text{Zn}+\text{HF}

ightarrow\text{ZnH}+\text{F} \): Incorrect formula for products (should be a salt and \( \text{H}_2 \), not \( \text{ZnH} \) and \( \text{F} \)).

• Option \( \text{Zn}+2\text{HF}

ightarrow\text{ZnF}_2+\text{H}_2 \): Zn has a +2 oxidation state, HF is \( \text{H}^+ \) and \( \text{F}^- \). The reaction is \( \text{Zn}+2\text{HF}=\text{ZnF}_2+\text{H}_2 \), which is balanced (1 Zn on both sides, 2 H on both sides, 2 F on both sides) and follows the single - displacement pattern.

• Option \( \text{Zn}+\text{HF}

ightarrow\text{ZnF}+\text{H} \): Incorrect formula (ZnF should be \( \text{ZnF}_2 \) for Zn's +2 charge, and H should be \( \text{H}_2 \) gas).

Answer:

\( \text{Zn}+2\text{HF}
ightarrow\text{ZnF}_2+\text{H}_2 \) (the option with this reaction equation)