The question asks about the color changes of methyl orange indicator in acidic and basic media. This is a fundamental concept in chemistry, specifically related to acid-base indicators. Recall the characteristic color changes of common indicators like methyl orange.
Based on these properties, methyl orange is red/pink in acidic medium and yellow in basic medium.
Correct Option: C) Red/pink in acidic medium, yellow in basic medium
The question asks about the basis on which olfactory indicators identify whether a solution is acidic or basic. Olfactory indicators are substances whose smell changes depending on whether they are in an acidic or basic medium. We need to identify the characteristic property that changes.
B) A change in their characteristic smell
Olfactory indicators are defined by their ability to change their smell in acidic or basic media. For example, the smell of onion or vanilla extract disappears or becomes less prominent in a basic solution, while it remains detectable in an acidic solution.
The question asks why concentrated sulphuric acid is used as a dehydrating agent. We need to understand the chemical properties of concentrated sulphuric acid, specifically its interaction with water, to determine the correct reason.
D) Has a strong affinity for water and removes moisture/water of crystallisation from substances. This statement accurately describes why concentrated sulphuric acid acts as a dehydrating agent. Its strong hygroscopic nature allows it to absorb water, making it useful in drying gases, removing water from organic compounds, and extracting water of crystallisation from hydrated salts.
The question asks about the standard range of the pH scale. The pH scale is a logarithmic scale used to specify the acidity or basicity of an aqueous solution. Understanding its definition and typical range is key to answering this question.
Correct Option: B) 0 to 14
The question asks for the correct mathematical definition of pH. pH is a measure of the acidity or alkalinity of an aqueous solution. It is fundamentally related to the concentration of hydrogen ions.
where \([\text{H}^+]\) represents the molar concentration of hydrogen ions (in moles per liter).
D) The negative logarithm (to the base 10) of the hydrogen ion concentration
This option perfectly matches the standard mathematical definition of pH, which is \( \text{pH} = -\log_{10}[\text{H}^+] \).
The pH scale is used to measure the acidity or basicity of an aqueous solution. It ranges from 0 to 14. The value of pH indicates the concentration of hydrogen ions (\(H^+\)) in the solution. A specific pH value corresponds to a neutral solution at room temperature.
B) Neutral — A solution with a pH of exactly 7 at room temperature is defined as neutral. This means it is neither acidic nor basic.