Why is sodium hydroxide used in the blue bottle experiment?

The sodium hydroxide converts gluconic acid into sodium gluconate. Methylene blue acts as an indicator, but also speeds the reaction by serving as an oxygen transfer agent. As it oxidizes glucose, methylene blue is reduced to form colorless leucomethylene blue.

Does glucose react with NaOH?

The reaction of glucose with dilute sodium hydroxide is known as Lobry de Bruyn-van Ekentein rearrangement. So, when glucose is treated with dilute NaOH, it gives a mixture of D-glucose, L-glucose and D-fructose.

What is the chemistry behind the use of methylene blue as an indicator?

Methylene blue is a redox indicator and is colourless under reducing conditions but regains its blue colour when oxidised. The removal of the blue colour is caused by the glucose which, under alkaline conditions, is reducing the methylene blue to a colourless form.

What is methylene blue used to test for?

The methylene blue test is a test to determine the type or to treat methemoglobinemia, a blood disorder.

Does methylene blue react with NaOH?

In the presence of sodium hydroxide, gluconic acid is converted to sodium gluconate. Methylene blue speeds up the reaction by acting as an oxygen transfer agent.

Why methylene blue is used in estimation of glucose?

Theory of Estimation of Glucose: As the supernatant liquid is blue and the precipitate is red in colour, there may be some difficulty in determination of end point accurately. Hence sometimes a methylene-blue indicator is employed for accurate determination of the end point.

Why is NaOH added to sucrose?

The sucrose in the molasses is hydrolyzed to glucose and fructose by invertase. The reducing sugars are then degraded by NaOH, the alkali being neutralized by the sugar acids produced, resulting in an increase of the ionic strength and consequently depression of the freezing point of the resulting solution.

What happens when glucose is treated with NaOH solution?

When glucose is treated with dilute NaOH, it forms a mixture of D-glucose, D-fructose and D-mannose due to reversible isomerisation. This reaction is generally known as Lobry de Bruyn-van Ekenstein.

What is the use of methylene blue for fish?

Methylene Blue is effective against superficial fungal infections of fish. The drug may be used as an alternative to Malachite Green for the control of fungus when it is known that the fish to be treated are sensitive. Methylene Blue is safe for use with fish eggs and fry for the prevention of fungal infections.

Why is methylene blue used in cellular respiration experiment?

This protcol uses yeast as the single-celled organism. This protocol investigates the effect of temperature on the rate of respiration of yeast. The rate of respiration of yeast can be assessed by using Methylene Blue – the removal of oxygen due to the repiration of the yeast causes the dye to become colourless.

What makes methylene blue go colorless?

Methylene blue is a redox indicator and is colorless under reducing conditions but regains its blue color when oxidized. The removal of the blue color is caused by the glucose which, under alkaline conditions, is reducing the methylene blue to a colorless form.

What gives the methylene blue dye its ionic blue color?

Methylthioninium chloride, commonly called methylene blue, is a salt used as a dye and as a medication. Methylene blue is a thiazine dye. It works by converting the ferric iron in hemoglobin to ferrous iron….Methylene blue.