Question: query regarding preparation of bordeaux mixture
Answer: a) bordeaux mixture (1%):
i) dissolve 100 g of powdered copper sulphate in 5 litters of water in a plastic bucket.
 ii) prepare milk of lime in another plastic bucket by dissolving 100 g of quick lime in 5 litres of water.
 iii) pour the copper sulphate solution and the milk of lime from the above two vessels into a third one by gently stirring the mixture all the while. this will give a final volume of 10 liters. 
iv) the mixture is to be tested before use for the presence of free copper which is toxic to the plant. dip a polished knife in the mixture. if the blade shows a reddish colour add more lime to the mixture till the blade does not show staining on dipping.