How Much You Know About Acids And Alkalis?

Lemon juice is known to be an acid because it contains citric acid, which gives it its sour taste. Acids are substances that have a pH level below 7 and can donate hydrogen ions when dissolved in water. Lemon juice has a low pH level, indicating its acidic nature. It can also react with alkaline substances to neutralize them. Therefore, lemon juice is classified as an acid.

pH paper, universal indicator, and red cabbage indicator can be used to determine whether something is an acid or alkali. These indicators change color in the presence of acidic or alkaline substances, allowing us to identify the nature of the substance being tested. By comparing the color change to a reference chart, we can determine whether the substance is acidic or alkaline.

In a neutral solution, the universal indicator turns green. This is because the universal indicator is a mixture of different pH indicators that change color at different pH levels. Green indicates a pH level around 7, which is considered neutral.

Orange juice contains acid because it is a citrus fruit juice, which naturally contains citric acid. This acid gives orange juice its tart and tangy taste.

The pH value of pure, unadulterated water is 7. This is because water is considered neutral, meaning it is neither acidic nor alkaline. A pH value of 7 indicates a balance between the concentration of hydrogen ions (acidic) and hydroxide ions (alkaline) in the water.

The pH paper turning red indicates that the solution is highly acidic. This suggests that it has a low pH value, typically below 7. A strong acid is a substance that completely dissociates in water, releasing a high concentration of hydrogen ions (H+). This leads to a highly acidic solution. Therefore, the correct answer is a strong acid.

The statement "Coke is an alkali" is false. Coke is a solid carbonaceous material that is derived from coal. It is primarily composed of carbon and does not possess the properties of an alkali, which is a type of base that can dissolve in water and produce hydroxide ions.

The presence of H ions makes a solution acidic because H ions are responsible for the release of hydrogen ions (H+) in a solution. These hydrogen ions increase the concentration of H+ ions in the solution, resulting in a low pH value and an acidic environment.

Among the options provided, baking powder is alkaline. Baking powder is a leavening agent used in baking, and it typically contains an alkaline substance, such as sodium bicarbonate (baking soda), which reacts with an acidic ingredient (like vinegar or lemon juice) to produce carbon dioxide gas, causing baked goods to rise. This reaction is what makes baking powder alkaline. Water and lime juice are not alkaline substances.