Comparing a value inside database with input value

My if statement doesn't recognize the textbox name ("ans"). What should I change? and where should I put it? I also want to know if my if statement is correct; I want to compare the value inside the database with the input value ("ans"). Thanks in advance.

<?php
    $con = mysql_connect("localhost", "root", "avtt123");
    mysql_select_db("arvintarrega",$con);

    $sql3 = "SELECT * from enumeration";
    $myData3 = mysql_query($sql3,$con); 

    echo '<form method = "POST">';

while($iden = mysql_fetch_array($myData))
{   
    echo '<center>' . $iden['question_number'] . '. ' . $iden['statement'] . ' <input type = "text" name = "ans"></input></center></br>';

    if($iden['correct_answer'] == $_REQUEST['ans'])
       {
        echo "Correct";
       }
    else
       {
        echo "Wrong";
       } 
}   
    echo '</form>';
?>