What is the exact volume of stannous chloride and water to be taken to prepare working solution according to Brays Method from a stock of 40% SnCl2? I referred many procedures but each one quotes different volume( 1 ml of 40% SnCl2 in 66 ml distilled water, 1 ml 40% SnCl2 in 330 ml distilled water, 1 ml of 40% SnCl2 in 1L of distilled water etc. Could anyone please help ? Which is the correct volume?