Answer:
Explanation:
In Polystrene, the molecular formula for the repeat unit =  ;
;
and the atomic weights of Carbon C = 12.01 g/mol
For Hydrogen, it is 1.01 g/mol
Hence, the repeat unit molecular weight is:
m = 8 (12.01 g/mol)+8(1.01 g/mol)
m = 96.08 g/mol + 8.08 g/mol
m = 104.16 g/mol
The degree of polymerization = no-average molecular weight/repeat unit molecular weight.
Mathematically;




 
        
             
        
        
        
Substitution Reactions are those reactions in which one nucleophile replaces another nucleophile present on a substrate. These reactions can take place via two different mechanism i.e SN¹ or SN². In SN¹ substitution reactions the leaving group leaves first forming a carbocation and nucleophile attacks carbocation in the second step. While in SN² reactions the addition of Nucleophile and leaving of leaving group take place simultaneously.
 
Example:
                        OH⁻  +  CH₃-Br     →     CH₃-OH  +  Br⁻
In above reaction,
                   OH⁻  = Incoming Nucleophile
                   CH₃-Br  =  Substrate
                   CH₃-OH  =  Product
                   Br⁻  =  Leaving group
Organic reactions are typically slower than ionic reactions because in organic compounds the covalent bonds are first broken, this breaking of bonds is a slower step, while, in ionic compounds no bond breakage is required as it consists of ions, so only bond formation takes place which is a quicker and fast step.
        
             
        
        
        
Answer:
Ba
Explanation:
<u>The elements  Calcium ( Ca ) and Cobalt ( Co ) , are both present in the same period , and across the period the atomic radius decreases from left to right , since , the atomic number increases , so the electrons increases , which in turns increases the effective nuclear charge , and hence the size decreases , </u>
Therefore , 
Calcium will have bigger atomic radii as compared to Cobalt .
Now, 
<u>The elements Barium ( Ba ) and Calcium ( Ca ) are , both are present in the same group , and down the group , atomic radii increases , since , as going down the group , the atomic number increase , so the shells increases , hence the size increases .</u>
Therefore , the atom with the largest radii is Barium .