JSFiddle - React, Tailwind, and code Playground

HTML

<form method="post">
  <table cellspacing="0" cellpadding="0" border="0" width="100%">
    <tr>
      <td style="padding-left:20px; padding-right:20px">
        <table cellspacing="3" cellpadding="2" border="0" width="100%">
          <tr>
            <td valign="top">1.</td>
            <td valign="top" colspan="2">Question</td>
          </tr>
          <tr>
            <td></td>
            <td width="5"><input value="question1_yes" name="question1" id="question1_yes" type="radio" /></td>
            <td><label for="question1_yes">Yes</label></td>
          </tr>
          <tr>
            <td></td>
            <td><input value="question1_no" name="question1" id="question1_no" type="radio" /></td>
            <td><label for="question1_no">No</label></td>
          </tr>
          <tr>
            <td></td>
            <td><input value="question1_dont_know" name="question1" id="question1_dont_know" type="radio" /></td>
            <td><label for="question1_dont_know">Don't know</label></td>
          </tr>
        </table>
      </td>
    </tr>
    <tr>
      <td style="padding-left:20px; padding-right:20px">
        <table cellspacing="3" cellpadding="2" border="0" width="100%">
          <tr>
            <td valign="top">2.</td>
            <td valign="top" colspan="2">Question</td>
          </tr>
          <tr>
            <td></td>
            <td width="5"><input value="question2_yes" name="question2" id="question2_yes" type="radio" /></td>
            <td><label for="question2_yes">Yes</label></td>
          </tr>
          <tr>
            <td></td>
            <td><input value="question2_no" name="question2" id="question2_no" type="radio" /></td>
            <td><label for="question2_no">No</label></td>
          </tr>
          <tr>
            <td></td>
            <td><input value="question2_dont_know" name="question2" id="question2_dont_know" type="radio" /></td>
            <td><label for="question2_dont_know">Don't know</label></td>
         ...

JavaScript

$('form').on('submit',function(e){
    // Counting number of questions
    arrayQuestions = new Array();
    $('input[type=radio').each(function(){
        arrayQuestions.push(this.name);
    });
    
    jQuery.unique( arrayQuestions );
    nbQuestion = arrayQuestions.length;
    nbAnsweredQuestion = $('input[type=radio]:checked').length;
    if(nbAnsweredQuestion < nbQuestion) {
         alert('You must answer every question');
         e.preventDefault();
    }
});