Questions

atoi()         Converts a string to an integer.

itoa()         Convert an integer to a string

gcvt()        Converts a floating-point number to a string

#include "stdlib.h"

main()

{

      char s[] = "12345";

      char buffer [15], string[20];

      int i;

      i = atoi (s);

      printf("\n%d",i);

       gcvt (20.141672, 4, buffer);

       printf ("\n%s", buffer);

       itoa(15, string,2);

        printf ("\n%s", string);

}

Here the given compound is MgSO4.

In the given compound, Sulphur (S) and Oxygen (O) are two non metals and Magnesium (Mg) is a metal.

In this compound, Sulphur and Oxygen reacts to form covalent bond and the metal Magnesium reacts with both non metals Sulphur and Oxygen to form ionic bonds.

Hence, in the given compound MgSO4 there are both covalent and ionic bonds.

Let that something be 'x'

From the given data,

x + x/5 = 21

5x + x/5 = 21

6x = 21 x 5

=> x = 17.5

Hence, that something is x = 17.5.