The answer would be 0.8 mol of x left over....
AND THATS IS WHY...refer to the pic below...
See if it is clear enough...
Given the mass percentage of HCl solution = 15.00 %
This means that 15.00 g HCl is present in 100 g solution
Moles of HCl = 
Density of the solution = 1.075 g/mL
Calculating the volume of solution from density and mass:

Converting volume from mL to L:

Calculating the molarity of HCl solution from moles and volume:

I₂ is the halogens which is darkest in colour than other.
<h3>What is halogen? </h3>
Halogens are the elements which belongs to group 17. Group 17 elements are known as halogens. They are highly electronegative in nature.
The last electronic configuration is ns2 np5. Since, one electron is less to get stable electronic configuration. Therefore, they accept one electron and get stable electronic configuration.
<h3>Why halogens are dark in colour? </h3>
As we move down the group, the darkness of colour increases. This is due to ionization energy which decreases as we move down the group. This is due to increase in the atomic size and decrease in nuclear form which further make high energy level to absorb lesser light and reflects deepen colour on moving down the group. Due to which they appears dark. Therefore, option A is the correct option.
Thus, we can concluded that I₂ is the halogens which is darkest in colour than other.
learn more about Halogens:
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Answer:
One calcium, two nitrogen, and six oxygen
Explanation: