Ratio of methyl red-methylene blue mixed indicator
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2 parts of 0.1% methyl red ethanol solution are mixed with 1 part of 0.1% methylene blue ethanol solution; different people have different understandings of this process – what is the correct method?
Reply to 1# nz200: I need to prepare a solution of 60 ml – how many grams of methyl red and how many grams of methylene blue are required?
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Reply 2# nz200 Is there anyone who can help me answer this?
Reply 1# nz200 is still not very clear. .
Weigh 0.1 g of methylene blue, dissolve it in ethanol, and dilute to 100 ml with ethanol. Weigh 0.1 g of methyl red, dissolve it in ethanol, and dilute to 100 ml with ethanol. Take 100 ml of the methyl red solution and 50 ml of the methylene blue solution, then mix them together
Reply to 6# Gaowei Chemical: Thank you for your answer. Here we have two different opinions – one is to calculate based on volume, and the other is to calculate based on mass. The results from these two methods are different; I’m not sure which one is correct.
Reply to 7# nz200: It’s calculated based on volume. In fact, it’s obvious from the literal meaning as well – how could weight be calculated per unit?
But many people don’t calculate it based on volume; there are still different opinions. Does anyone know the correct method?
Reply to 9# nz200: When using an indicator, a volume ratio is generally applied; percent concentration is not required and does not need to be very precise. For the solute, its weight is measured, while for the solvent, its volume is used – two or one portion of volume is sufficient, unless the method specifies a mass ratio.
We configured it the same way; it just seems that the color of the indicator is quite light. Could we use a higher concentration?