i dont understand that how thhe lime water changes into milky and what is intret gas
When air passes to the test tube, then lime water present in test tube turns milky because in air carbon dioxide is present, which when react with lime water, it forms calcium carbonate which is milky in color. Lime water is calcium hydroxide, when CO2 gas is passed in this solution, then due to the formation of CaCO3, solution turns milky in color.
Ca(OH)2 + CO2 → CaCO3 + H2O
Calcium carbonate is milky in color, so on passing carbon dioxide in lime water, solution turns to milky in color.
I could not interpret your query, please recheck your second query and do get back to us.