Answer : The correct option is, (b) 22.5 M
Explanation : Given,
Mass of calcium nitrate tetrahydrate = 266 g
Molar mass of calcium nitrate tetrahydrate = 236.15 g/mole
Volume of solution = 
Molarity : It is defined as the moles of solute present in one liter of solution.
Formula used :

Now put all the given values in this formula, we get:

As calcium nitrate tetrahydrate dissociate to give 1 mole of calcium ion, 2 moles of nitrate ion and 4 moles of water.
The concentration of nitrate ion = 
Thus, the concentration of nitrate ion is, 22.5 M
The answer to this question will be c
they're experts in iron metallurgy
The bantu was originated from the southern part of Africa ( round republic of Congo) , and has been the expert of utilizing iron among the ancient tribe
Mostly they use it for their Agricultural system ( such as their Irrigation system, for their agricultural tools, etc)
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<span>Answer:
K because it is metal and typically forms ionic bonds. Ar is also unlikely to form any bonds because it has a full outer shell of electrons, but it can form covalent bonds.</span>