What is the essential solute and concentation of saline water?

0.9% NaCl

The answer is 0.9% NaCl.

Saline water is a type of solution that contains dissolved salt. The essential solute and concentration of saline water is 0.9% \(NaCl\). This means that there are 0.9 grams of \(NaCl\) dissolved in 100 grams of water.

\(NaCl\) is a type of salt that is made up of sodium and chloride ions. Sodium ions are positively charged, while chloride ions are negatively charged. The presence of these ions in saline water helps to regulate the osmotic pressure of the blood. Osmotic pressure is the pressure that is exerted by a solution to prevent the movement of water across a semipermeable membrane.

Saline water is also used in a variety of other applications, such as in food preservation, in the production of soap and detergents, and in the treatment of water for drinking and bathing.

The other options are incorrect. \(NH_4Cl\) is not an essential solute in saline water, and its concentration is typically much lower than 0.9%. 1.2% \(NH_4Cl\) is a much higher concentration than is typically used in saline water, and it can be harmful to humans.