Question

A student is trying to identify an unknown metal, X. When he/she places it in copper-sulphate solution, there is a reaction. Red-brown pieces of copper fall to the bottom of the test tube. When the student places metal X in magnesium chloride solution, nothing happens. a) Give two suggestions for the identity of metal X. b) How could the student find out which of these is the true identity of metal X?

Answer 1

Hey MATE!

a) The two suggestions to find out element X are :

1) Element X is more reactive than Copper.

2) Element X is less reactive than Magnesium.

b) Both of the identification given for element X are true if it lies between Magnesium and Copper in Reactivity Series.

There may be more than one element if we consider reactivity series.

Hope it helps


Hakuna Matata :))

Answer 2

We are given that a student is trying to identify an unknown metal, X. Let us have a look at the metal reactivity series as follows in descending order.

K>Na>Ca>Mg>Al>Zn>Fe>Pb>[H] >Cu >Hg>Ag>Au

• So, as we see that in a compound a metal can be displayed if and only if the reacting metal is highly reactive than the metal in the compound. As per the question we can write the equation as follows:

CuSO4 + X ------------->? + Cu

• So, there are 8 metals more reactive than copper to displace it.

• When the metal is placed in magnesium chloride solution, nothing happens which shows that it is less reactive than magnesium.

a) The two proposals to find out element X are:

1) Element X is highly reactive than Copper.

2) Element X is lies below Magnesium in the series.

b) To identify the metal, we need to see the change in the color of the solution.

• If it is clear colorless aqueous solution, it is aluminum.
• If it is colorless the metal is zinc.
• If it is light green solution it is iron.
• If it appears as a white crystalline solid it is Lead sulfate

Both of the proof of identity given for element X are true if it lies between Magnesium and Copper in Reactivity Series.

#SPJ2