Investigation of the Concentration of Reducing Sugar

Biology Lab Report

Investigation of the concentration of reducing sugar in solution A, B, C

Results:

2ml of solution A, B, C and distilled water was pipetted separately into four test tubes with each containing 3ml of Benedict’s reagent, which then are placed into hot bath for few minutes. The amounts of brick-red precipitate formed were recorded and results were shown below:

Amount of brick-red precipitate formed in each solution |

Solution | A | B | C | Distilled water |

Amount of brick-red precipitate formed | +++ | +++ | ++ | - |

Key:

+++: Large amount of brick-red precipitate is formed

++: Medium amount of brick-red precipitate is formed

+: Small amount of brick-red precipitate is formed

-: No brick-red precipitate is formed

Large amount of brick-red precipitate were formed in solution A and B. To further compare the concentration of reducing sugar in both solutions, solutions were then diluted by ten folds, and results were shown below:

Amount of brick-red precipitate formed in solution A and B (diluted) |

Solution | A | B |

Amount of brick-red precipitate formed | + | ++ |

Both solution formed brick-red precipitates.

Ratio of the amount of brick-red precipitate formed in each solution |

Solution | A | B | C |

Diluted | 1 | 2 | 2 |

Concentrated | 5 | 10 | 1 |

Discussion

Interpretation

-No reducing sugar was tested by Benedict’s reagent in distilled water, therefore no precipitate was formed.

-Lots of brick-red precipitates were formed in the solution A and B. Since 3ml of Benedict’s reagent was not enough to react with all reducing sugar in both solutions, therefore it required to dilute both solution by ten folds in order to react all reducing sugar.

Limitation

-5 minutes may be too short to allow the mixture to react completely

Errors

-The time of allowing the test tubes placed in hot water bath may not be accurate, which may lead to non-accurate results.

Improvements

-Place all test...