Identify the liquid droplets collected on the cooler part of the test tube when ferrous sulphate crystals are heated?

When ferrous sulfate crystals are heated, they undergo dehydration and decomposition, resulting in the release of water vapor. This vapor condenses on the cooler parts of the test tube, forming liquid droplets. These droplets consist mainly of water, which is a byproduct of the thermal decomposition of ferrous sulfate.