Question

Which of the following does not react with oxygen directly?
(A) Zn
(B) Ti
(C) Pt
(D) Fe

Answer 1

The metal which is not from the first row of the d-block of the periodic table will not react with oxygen. The metals which have in general low reactivity and do not react with oxygen is called noble metals.

Complete step by step solution:
Here, we are given some metals and we will need to check its reactivity with oxygen in order to find which one will not react with it.
- Almost all the metals react with oxygen and form their corresponding oxides depending on their valency. There is an exception that noble metals do not react with oxygen and so they do not form oxides while reacting with gaseous oxygen.
- The noble metals are the ones that do not react with oxygen gas and do not get corroded. The metals like Gold, Platinum, Silver, Ruthenium, etc are the examples of noble metals.
- So, Platinum whose chemical symbol is Pt does not react with oxygen.
- The other metals given in the options are Zinc, Titanium and Iron. All the three metals are of d-block and are placed in the first row of d-block elements. None of the metals from the first row of the d-block is characterized as noble metal. So, Zinc will react with oxygen to make Zinc oxide (ZnO), Titanium and iron will also react with oxygen to give their oxides $Ti{{O}_{2}}$ and FeO respectively.

Thus, we can say that the correct answer of this question is (C).

Note: The reason why some metals have relatively low reactivity is their completely filled d-subshell. As an example Copper and Platinum have complete d-subshell in their electronic configuration.