An indicator solution was obtained by boiling a flower in water.
Two solutions were tested with this indicator.
Which row of the table correctly identifies the colour of each solution?
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An indicator solution was obtained by boiling a flower in water.
Two solutions were tested with this indicator.
Which row of the table correctly identifies the colour of each solution?
→ pH can be calculated from the
The concentration of hydrochloric acid in a solution was determined by an acid base titration using a standard solution of sodium carbonate.
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a. →
→
→ An accurate weight of
b. 0.2425 mol L–¹
c. → This is a strong acid / weak base titration.
→ Its equivalence point will occur at a pH less than seven and phenolphthalein changes colour in the pH range 10 – 8.3.
→ Phenolphthalein indicator would therefore signal the end point before equivalence (i.e. with a lower volume of acid).
→ The calculated concentration of
a. →
→
→ An accurate weight of
b.
c. → This is a strong acid / weak base titration.
→ Its equivalence point will occur at a pH less than seven and phenolphthalein changes colour in the pH range 10 – 8.3.
→ Phenolphthalein indicator would therefore signal the end point before equivalence (i.e. with a lower volume of acid).
→ The calculated concentration of
Which indicator in the table would be best for distinguishing between lemon juice (pH = 2.3) and potato juice (pH = 5.8)?
If Methyl orange is used:
→ Lemon juice would be red, potato juice yellow
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a. Methodology:
→ Collect plant material that is a natural indicator of pH. Examples include rose petals and red cabbage.
→ Cut the coloured parts into small pieces.
→ Place material into a beaker with water and boil until the solution becomes coloured.
→ Allow the mixture to cool at room temperature.
→ Decant the liquid into a container, leaving the solid behind.
b. → Prepare test tubes of various acids and bases (pH of each is known).
→ Add some of the indicator to each test tube.
→ Record the natural indicator colour of each example and whether it differentiates between acids and bases and their concentrations.
a. Methodology:
→ Collect plant material that is a natural indicator of pH. Examples include rose petals and red cabbage.
→ Cut the coloured parts into small pieces.
→ Place material into a beaker with water and boil until the solution becomes coloured.
→ Allow the mixture to cool at room temperature.
→ Decant the liquid into a container, leaving the solid behind.
b. → Prepare test tubes of various acids and bases (pH of each is known).
→ Add some of the indicator to each test tube.
→ Record the natural indicator colour of each example and whether it differentiates between acids and bases and their concentrations.
The diagram represents the titration curve for a reaction between a particular acid and a particular base.
Which indicator would be best for this titration?
→ The pH range at which isopicramic acid exhibits a colour change includes the point at which the acid and base react in equal amounts (equivalence point), which is at approximately pH 5.
→ The colour change can be used to identify when the equivalence point has been reached in a titration.
Which indicator in the table would be best for distinguishing between a face cleanser (pH = 5.0) and a soap (pH = 9.0)?
→ The phenol red would be yellow for face cleanser (pH of 5.0) and red for soap (pH of 9.0).
→ The other indicators would give off the same colour for both.