when to free pointer in C and how to know if it is freed

I am new in C, trying to figure out about memory allocation in C that I kinda confused

#include <stdio.h>
#include <stdlib.h>

typedef struct
{
    int a;
} struct1_t;

int main()
{
    funct1(); //init pointer
    return 1;
}


int funct2(struct1_t *ptr2struct)
{
    printf("print a is %d\n",ptr2struct->a);
    //free(ptr2struct);
    printf("value of ptr in funct2 is %p\n", ptr2struct);
    return 1; //success
}


int funct1(){

    struct1_t *ptr2struct = NULL;
    ptr2struct = malloc(sizeof(*ptr2struct));
    ptr2struct->a = 5;
    printf("value of ptr before used is %p", ptr2struct);
    if (funct2(ptr2struct) == 0) {
        goto error;
    }
    free(ptr2struct);

    printf("value of ptr in funct1 after freed is is %p\n", ptr2struct);
    return 1;

error:
    if(ptr2struct) free(ptr2struct);
    return 0;
}

I have funct 1 that calls funct 2, and after using the allocated pointer in funct1, I try to free the pointer. And I create a case where if the return value in funct2 is not 1, then try again to free the pointer.

My question is below

which practice is better, if I should free the memory in funct2 (after I pass it) or in funct1 (after I finish getting the return value of funct1) The second thing is whether this is correct to make a goto error, and error:

if(ptr2struct) free(ptr2struct); 

My third question is , how do I check if the allocated value is already freed or not? because after getting the return value, I free the pointer, but if I print it, it shows the same location with the allocated one (so not a null pointer).