Question

what is the least reactive metal according to the data? yes = reaction occurs no = no reaction occurs

Explanation:

Step1: Understand the reactivity concept

A less reactive metal won't be displaced by other metals in a reaction. If a metal's nitrate solution doesn't react (shows 'No') with other metal - based solutions, it indicates lower reactivity.

Step2: Analyze the data for each metal

• For \(Hg\): \(Hg(NO_3)_2\) reacts with \(Ba\), \(Co\), \(Li\) (shows 'Yes' in their rows). But when other metal nitrates (\(Ba(NO_3)_2\), \(Co(NO_3)_2\), \(LiNO_3\)) are checked against \(Hg\) (i.e., looking at the columns for \(Hg\)), \(Ba(NO_3)_2\) (row of \(Ba(NO_3)_2\) and column of \(Hg\)) shows 'No' (no reaction from \(Ba\) to \(Hg\)), \(Co(NO_3)_2\) (row of \(Co(NO_3)_2\) and column of \(Hg\)) shows 'No' (no reaction from \(Co\) to \(Hg\)), \(LiNO_3\) (row of \(LiNO_3\) and column of \(Hg\)) shows 'No' (no reaction from \(Li\) to \(Hg\)).
• For \(Ba\): \(Ba(NO_3)_2\) reacts with \(Li\) (shows 'Yes' in the row of \(Ba(NO_3)_2\) and column of \(Li\)).
• For \(Co\): \(Co(NO_3)_2\) reacts with \(Ba\) and \(Li\) (shows 'Yes' in the row of \(Co(NO_3)_2\) and columns of \(Ba\) and \(Li\)).
• For \(Li\): \(LiNO_3\) doesn't react with other metals in terms of displacement (but it's a very reactive metal in general, and from the table, other metals react with its salts more actively compared to \(Hg\)).

Since no other metal can displace \(Hg\) from \(Hg(NO_3)_2\) (as seen from the 'No' responses in the columns for \(Hg\) in \(Ba(NO_3)_2\), \(Co(NO_3)_2\), \(LiNO_3\) rows), \(Hg\) is the least reactive among the given metals.

Answer:

\(Hg\)