Solids are usually more dense than liquids and gases.
The answer is (3) metallic. Cobalt is a transition metal, so it can't be covalent bonds, which bond non-metals, therefore eliminating choice 1 and 2. Ionic bonds are between metals and non metals, but solid cobalt does not have a non metal, eliminating choice 4 as well. Metallic bonds are bonds between metals, therefore the answer is (3) metallic.
Answer:
Mass = 5.56 g
Explanation:
Given data:
Mass of Cl₂ = 4.45 g
Mass of NaCl produced = ?
Solution:
Chemical equation:
2Cl₂ + 4NaOH → 3NaCl + NaClO₂ + 2H₂O
Number of moles of Cl₂:
Number of moles = mass/molar mass
Number of moles = 4.45 g/ 71 g/mol
Number of moles = 0.063 mol
Now we will compare the moles of Cl₂ with NaCl.
Cl₂ : NaCl
2 : 3
0.063 : 3/2×0.063 =0.095 mol
Mass of NaCl:
Mass = number of moles × molar mass
Mass = 0.095 mol × 58.5 g/mol
Mass = 5.56 g

Actually Welcome to the concept of Ions .
If we see the reaction.
H2SO4 ==> 2H+ + (SO4)2-
Here you can see, H+ ( Hydrogen ions) and (SO4) 2- ( sulphate ions) are the ions when the H2SO4 is dissolved in water.