Answer : The correct option is, (2) Cr (Chromium)
Explanation :
The reactivity series of metal are arranged of the reactivity from the highest to the lowest. Reactivity series is used to determine the products of the single displacement reactions. In the single displacement reaction, the most reactive metal displaces the least reactive metal.
From the given reactivity series we conclude that there are two metal (Mg and Cr) are more reactive metal than the Ni and there are two metal (Pb and Cr) are less reactive metal than the Zn. So, the Cr (Chromium) is the metal which is more active than Ni and less active than Zn.
Hence, the correct option is, (2) Cr
Answer:
The following reaction will occur at cathode:

Explanation:
The two half reaction during electrolysis of aqueous nickel sulfate will be
a) anode reaction :
Water will undergo oxidation and will evolve oxygen gas at anode as shown in the given reaction:

b) Cathode reaction: The reduction of Nickel ion will occur by gain of two electrons as shown in the given equation:

Thus the overall reaction will be:

<h3>→soft and reactive metals. </h3>
Explanation:
<h3>Alkali metals are soft and reactive metals. They react vigorously with water and become more reactive. And other hand halogens are reactive non metals. ... Halogens can be solid, liquid, gaseous at room temperature and the melting point increase when they get bigger.</h3>
<h2>#CAREYINGTOLEARN❤️</h2>
heating is repeated to ensure all water molecules have evaporated