There are 6 bottles of water. Salt is added to the first one, a strong acid namely HCl to the 2nd one, a strong base namely calcium hydroxide to the 3rd one, a weak acid namely vinegar to the 4th one, a weak base namely baking soda to the 5th one and the 6th bottle of water is left in the same way.

What will happen to each bottle, what will each bottle look like and how will each bottle smell after 6 days?

It is difficult to predict with certainty what will happen to each bottle after 6 days, as it depends on the quantity and concentration of the substances added to the water, as well as the environmental conditions. However, here are some possible outcomes:

1. The bottle with salt added: Salt is a stable compound that does not react with water, so the bottle will likely look similar to the other bottles with clear water. However, the water may taste slightly salty.

2. The bottle with HCl added: Hydrochloric acid is a strong acid that can react with metals, carbonates, and other bases. If the concentration of HCl is high enough, the water may turn yellowish or brown due to the formation of iron(III) chloride or other metal chlorides. The water may also give off a strong acidic odor and taste sour.

3. The bottle with calcium hydroxide added: Calcium hydroxide is a strong base that can react with acids to form salts and water. If the concentration of calcium hydroxide is high enough, the water may turn cloudy or milky due to the formation of calcium carbonate. The water may also smell slightly like ammonia.

4. The bottle with vinegar added: Vinegar is a weak acid that can react with bases to form salts and water. If the concentration of vinegar is high enough, the water may turn slightly yellowish or brown due to the formation of copper(II) acetate or other salts. The water may also smell slightly like vinegar.

5. The bottle with baking soda added: Baking soda is a weak base that can react with acids to form salts and water. If the concentration of baking soda is high enough, the water may turn slightly cloudy or milky due to the formation of calcium carbonate. The water may also smell slightly like baking soda.

6. The bottle with no additives: This bottle will likely look and smell similar to the other bottles with clear water, unless there are other factors (such as contamination) that affect the water quality.

After 6 days, here's what will happen to each bottle:

1st bottle (salt added): The water in the bottle with salt added will remain clear and unchanged. It will not have any distinct odor since salt does not have a strong smell.

2nd bottle (HCl added): The addition of the strong acid, HCl, will cause the water to become more acidic. It may start to appear cloudy or have a slight yellowish tint. It will have a strong acidic smell due to the release of hydrogen chloride gas.

3rd bottle (calcium hydroxide added): The addition of the strong base, calcium hydroxide, will cause the water to become more alkaline. It may appear cloudy or have a white precipitate formed. It will have a soapy or bitter smell due to the release of calcium hydroxide.

4th bottle (vinegar added): The weak acid, vinegar, will not significantly alter the appearance of the water. It may appear slightly cloudy, but not as pronounced as the previous bottles. It will have a sour smell due to the presence of acetic acid.

5th bottle (baking soda added): The addition of the weak base, baking soda, will cause the water to become slightly alkaline. It may appear slightly cloudy or have a white precipitate formed. It may have a faint odor of baking soda or a slightly soapy smell.

6th bottle (control): The water in the sixth bottle, which was left unchanged, will remain clear and odorless.

It's important to note that these observations are based on general chemical reactions and may vary depending on the specific concentrations and amounts of substances added to each bottle.