1. Carbon Dioxide (CO2): This is the gas we exhale and is also a significant component of the atmosphere. It dissolves in water to form carbonic acid (H2CO3), which contributes to the acidity of rainwater.

2. Ammonia (NH3): This gas is used in many industrial processes and is also produced naturally by decomposition. It dissolves in water to form ammonium hydroxide (NH4OH), a weak base.