I want to calculate the path aliases for array of nids. But it always give me the path for latest content. Can anyone please help me.

$query = new EntityFieldQuery();
$query->entityCondition('entity_type', 'node');
$query->entityCondition('bundle', 'product');
$query->propertyCondition('status', 1);
$query->fieldCondition('field_product_sub_cat', 'tid',array($leaf_nodes));
$result = $query->execute();
if (isset($result['node']))
{
  $product_childnid = array_pop(array_keys($result['node']));
}
$path = 'node/'.$product_childnid;
$product_alias = drupal_get_path_alias($path);

I want to calculate the path aliases for array of nids. But it always give me the path for latest content. Actually I can not get all the nids. My array structure is like below. When I used the command product_childnid = array_pop(array_keys($result['node'])); I always get the 100 nid but I want all of them for path aliases.

Array
(
[node] => Array
    (
        [78] => stdClass Object
            (
                [nid] => 78
                [vid] => 78
                [type] => product
            )

        [80] => stdClass Object
            (
                [nid] => 80
                [vid] => 80
                [type] => product
            )

        [82] => stdClass Object
            (
                [nid] => 82
                [vid] => 82
                [type] => product
            )

        [84] => stdClass Object
            (
                [nid] => 84
                [vid] => 84
                [type] => product
            )

        [86] => stdClass Object
            (
                [nid] => 86
                [vid] => 86
                [type] => product
            )

        [88] => stdClass Object
            (
                [nid] => 88
                [vid] => 88
                [type] => product
            )

        [90] => stdClass Object
            (
                [nid] => 90
                [vid] => 90
                [type] => product
            )

        [92] => stdClass Object
            (
                [nid] => 92
                [vid] => 92
                [type] => product
            )

        [94] => stdClass Object
            (
                [nid] => 94
                [vid] => 94
                [type] => product
            )

        [100] => stdClass Object
            (
                [nid] => 100
                [vid] => 100
                [type] => product
              )
          )
  )

$query = new EntityFieldQuery();
$query->entityCondition('entity_type', 'node');
$query->entityCondition('bundle', 'product');
$query->propertyCondition('status', 1);
$query->fieldCondition('field_product_sub_cat', 'tid',array($leaf_nodes));
$result = $query->execute();
if (isset($result['node']))
{
  $product_childnid = array_pop(array_keys($result['node']));
}
$path = 'node/'.$product_childnid;
$product_alias = drupal_get_path_alias($path);