Explain the ''Rancidity'' terms with one example.
Rancidity :
The process of oxidation of fats and oils that can be easily noticed by the change in taste and smell is known as rancidity.
For example, the taste and smell of butter changes when kept for long.
Rancidity can be avoided by:
$1.$ Storing food in air tight containers
$2.$ Storing food in refrigerators
$3.$ Adding antioxidants
$4.$ Storing food in an environment of nitrogen
Oil and fat containing food items are flushed with nitrogen. Why ?
What does one mean by exothermic and endothermic reactions ? Give examples.
Write the balanced equation for the following chemical reactions.
$(i)$ Hydrogen $+$ Chlorine $\to $ Hydrogen chloride
$(ii)$ Barium chloride $+$ Aluminium sulphate $\to $ Barium sulphate $+$ Aluminium chloride
$(iii)$ Sodium $+$ Water $\to $ Sodium hydroxide $+$ Hydrogen
Write one equation each for decomposition reactions where energy is supplied in the form of heat, light or electricity.
Write the balanced chemical equation for the following and identify the type of reaction in each case.
$(a)$ Potassium bromide $(aq)$ $+$ Barium iodide$(aq)$ $\rightarrow$ Potassium iodide$(aq)$ $+$ Barium bromide$(s)$
$(b)$ Zinc carbonate$(s)$ $\rightarrow$ Zinc oxide$(s)$ $+$ Carbon dioxide$(g)$
$(c)$ Hydrogen$(g)$ $+$ Chlorine$(g)$ $\rightarrow$ Hydrogen chloride$(g)$
$(d)$ Magnestum $(s)$ $+$ Hydrochloric acid$(aq)$ $\rightarrow$ Magnesium chloride$(aq)$ $+$ Hydrogen $(g)$