ASSERTION: Auric chloride ($AuC{l_3}$) solution cannot be stored in a vessel made of copper, iron, nickel, chromium, zinc or tin.
REASON: Gold is a very precious metal.
A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
C. Assertion is correct but Reason is incorrect
D. Both Assertion and Reason are incorrect

Hint: We know that Reduction potential is the tendency of a chemical species to get reduced when it gains an electron and it is also defined as with electrochemical reference of hydrogen, which is known with the reduction potential of zero. Here, we have to check the reactivity of gold and compare it with the reactivity of copper, iron, nickel, chromium, zinc or tin by checking the reduction potential values.

Complete step by step answer:
Let’s understand an electrochemical cell. It is a device which can generate electrical energy from the chemical energy in chemical reactions occurring in it, or it can use electrical energy supplied to it to facilitate chemical reactions in it.
Now let us see the assertion. The assertion says Auric chloride ($AuC{l_3}$) solution cannot be stored in a vessel made of copper, iron, nickel, chromium, zinc or tin. It is true because gold has higher reduction potential, so less reactive and whenever we put gold chloride solution in copper, iron, zinc, or tin which are very reactive, then electrochemical cells are formed. After this, reduction of gold takes place because active metals can easily displace gold from its solution.
Now let us see the reason. The reason says gold is a very precious metal. This is true but does not explain the assertion.

So, the correct answer is Option B.

Note: It is to be noted that reactivity series is the list of metals arranged in order of decreasing reactivity in a table. In the activity series of metals, sodium and potassium are two most reactive metals and the gold and platinum are least reactive metals.