Give reasons for the following:
a. Sodium metal is always kept immersed in kerosene oil.
b. Zinc metal displaces iron from its salt solution.
c. Colour of copper sulphate solution changes when zinc strip is added in it.
d. Aluminium is used for making electrical wires.
Answers
Answer:
Explanation:
A.Sodium metal is highly reactive. If it is kept open it can explosively react with oxygen, carbon dioxide and moisture present in the air. They catch fire and start burning.To prevent this explosive reaction and the After Effects sodium is kept immersed in kerosene oil
B.When a metal react with the salt solution and displaces the metal present in it, is called displacement reaction. Iron can displace copper from its salt solution because iron is placed higher in the activity series than copper and is more reactive than copper
C.When zinc is added to copper sulphate solution, then the zinc metal displaces copper from copper sulphate to form zinc sulphate. This happens because zinc is more reactive than copper. CuSO4 solution has a blue colour while ZnSO4 solution is colourless. Zn(s) + CuSO4(aq) -> Cu(s) + ZnSO4 (aq).
D.Utility companies have used aluminum wire for electrical transmission in power grids since around the late 1800s to the early 1900s. It has cost and weight advantages over copper wires. Aluminum wire in power transmission and distribution applications is still the preferred material today.