Q. 73.9( 12 Votes )
Name the reagent which is able to dissolve gold and platinum.
Gold and Platinum belong to class of noble metals in the sense that gold and platinum do not react with almost any chemical reagent.
Aqua Regia is the chemical mixture which consists of 3 parts of concentrated hydrochloric acid and 1 part of concentrated nitric acid and this mixture can dissolve gold and platinum. The reaction is as follows:
Au + HNO3 + 4 HCl → HAuCl4 + NO + 2 H2O
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i. What is observed when a solution of potassium iodide is added to a solution of lead nitrate taken in a test tube?
ii. What type of reaction is this?
iii. Write a balanced chemical equation to represent the above reaction.
A brown substance ‘X’ on heating in air forms a substance ‘Y’. When hydrogen gas is passed over heated ‘Y’, it again changes back into ‘X’.
i. Name the substance ‘X’ and ‘Y’
ii. Name the type of chemical reactions occurring during both the changes.
iii. Write the chemical equations of the reactions.Xam idea - Science