Incorrect Statement: River water is salty water.

Explanation:
Water is a vital substance that covers about 71% of the Earth's surface and is essential for all forms of life. It exists in three main forms: solid (ice), liquid (water), and gas (water vapor), and can change from one form to another through the processes of freezing, melting, evaporation, and condensation.

Water in Rivers:
Rivers are natural water bodies that flow towards the sea. They are formed by the accumulation of water from various sources such as rain, melting snow, and underground springs. River water is primarily freshwater, not salty water. The water in rivers comes from precipitation and is not directly connected to the ocean, which is salty. Therefore, statement b) "River water is salty water" is incorrect.

Salinity:
Salinity refers to the amount of dissolved salts in water. While seawater is saline due to its high salt content, freshwater sources like rivers, lakes, and groundwater are generally low in salinity. However, it is important to note that the salinity of water can vary depending on factors such as geological formations, human activities, and proximity to the ocean. For example, in some regions, rivers can pick up salts from the surrounding rocks and soil, leading to slightly higher salinity levels.

Hand Pumps and Underground Water:
Hand pumps are devices used to extract water from underground sources such as wells or boreholes. Underground water, also known as groundwater, is naturally occurring water found beneath the Earth's surface in spaces between soil particles and within rock formations. Hand pumps are specifically designed to draw water from these underground sources by creating a vacuum or suction. Therefore, statement c) "Hand pumps can be used to draw underground water" is correct.

Conclusion:
In conclusion, the incorrect statement regarding water is b) "River water is salty water." River water is primarily freshwater, not salty water. It is important to understand the different forms of water and the sources from which it is obtained to have a comprehensive understanding of this essential substance.