Question

1. choose the best answer.

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

1. choose the best answer.

what is always produced during a combustion reaction?
○ metals
○ hydrogen gas
○ salts
○ water

Explanation:

Question 13

• Precipitation reactions involve the formation of a solid precipitate from dissolved ions, not proton transfer.
• Acid - base reactions (by the Brønsted - Lowry definition) involve the transfer of protons ($H^+$ ions), where an acid donates a proton and a base accepts a proton.
• Redox reactions involve the transfer of electrons, not protons.

• Combustion reactions typically involve a substance reacting with oxygen. For example, the combustion of hydrocarbons (like methane $CH_4 + 2O_2

ightarrow CO_2+2H_2O$) or other organic compounds.

• Metals are not always produced (combustion of non - metals or compounds without metals won't produce metals).
• Hydrogen gas is not always a product (e.g., combustion of carbon - based compounds with sufficient oxygen may not produce $H_2$).
• Salts are not always produced (combustion of substances like hydrocarbons produces $CO_2$ and $H_2O$, not salts).
• Water is always produced when there is hydrogen in the reactant (which is common in many combustible substances like fuels) as the hydrogen combines with oxygen.

Answer:

B. Acid - base

Question 14