Answer:
1.They are all in the second group of the periodic table
2.They are an alkaline earth metal
3.They all have a shine to them
4.They are all highly reactive
5.They have a silver/white to them
6.They can all be found in the Earths crust
I'm not really sure of any others that they have in common and I thought to give extra so you could choose.
The mass of NaCl sample has been 24.3 g. Thus, option A is correct.
The heat of fusion has been the amount of heat required to convert 1 mole of substance into solid to liquid state.
The heat required has been given as:

<h3>Computation for the mass of NaCl</h3>
The given solution has heat of fusion, 
The heat required to melt the sample has been, 
Substituting the values for the mass of NaCl

The mass of NaCl sample has been 24.3 g. Thus, option A is correct.
Learn more about heat of fusion, here:
brainly.com/question/87248
Answer: A 59.5 degree celcius
The equation that we will use to solve this problem is :
PV = nRT where:
P is the pressure of gas = 1.8 atm
V is the volume of gas = 18.2 liters
n is the number of moles of gas = 1.2 moles
R is the gas constant = 0.0821
T is the temperature required (calculated in kelvin)
Using these values to substitute in the equation, we find that:
(1.8)(18.2) = (1.2)(0.0821)(T)
T = 332.5 degree kelvin
The last step is to convert the degree kelvin into degree celcius:
T = 332.5 - 273 = 59.5 degree celcius
When in doubt pick C I don’t really know the answer but I just pick C
The correct answer is d) methane (

)
The other options are elements.