Question

1. match the name of the reaction to the equation.

4c₅h₉o + 27o₂ → 20co₂ + 18h₂o

1. choose the best answer.

____ reactions involve the transfer of protons (h⁺ ions).
○ acid - base
○ precipitation
○ redox

1. match the name of the reaction to the equation.

3pb + 2h₃po₄ → 3h₂ + pb₃(po₄)₂

Explanation:

Question 18 (Match reaction name to equation \( \boldsymbol{4C_5H_9O + 27O_2

ightarrow 20CO_2 + 18H_2O} \))

Step1: Identify reaction type

The equation shows a compound (\( C_5H_9O \)) reacting with \( O_2 \) to produce \( CO_2 \) and \( H_2O \). This is a combustion reaction (burning of an organic compound in oxygen to yield carbon dioxide and water).

Step2: Confirm combustion characteristics

Combustion reactions of organic compounds (like hydrocarbons or oxygen - containing organics) follow the pattern: Organic compound + \( O_2
ightarrow CO_2 + H_2O \). Here, \( C_5H_9O \) is an organic compound, and the products are \( CO_2 \) and \( H_2O \), so it's a combustion reaction.

• Acid - base reactions: By the Brønsted - Lowry definition, acid - base reactions involve the transfer of protons (\( H^+ \) ions). An acid donates a proton, and a base accepts a proton.
• Precipitation reactions: These involve the formation of an insoluble solid (precipitate) from the reaction of two soluble ionic compounds. No proton transfer occurs.
• Redox reactions: These involve the transfer of electrons (change in oxidation states), not protons.

So the reaction type that involves proton transfer is acid - base.

Step1: Analyze reactants and products

We have a metal (Pb) reacting with an acid (\( H_3PO_4 \)) to produce hydrogen gas (\( H_2 \)) and a salt (\( Pb_3(PO_4)_2 \)). The general form of a single - replacement reaction (specifically a metal - acid reaction) is: Metal + Acid \(
ightarrow \) Hydrogen gas + Salt.

Step2: Confirm single - replacement

In this reaction, Pb (a metal) replaces the \( H^+ \) in \( H_3PO_4 \) (the acid) to form \( H_2 \) and the salt \( Pb_3(PO_4)_2 \). This fits the pattern of a single - replacement reaction (also called a displacement reaction), where one element replaces another in a compound.

Answer:

The reaction is a Combustion Reaction (matches the equation as it is the burning of \( C_5H_9O \) in \( O_2 \) to form \( CO_2 \) and \( H_2O \)).

Question 19 (Choose best answer for proton - transfer reactions)