Cho 3,1 gam <span class="MathJax_Preview" style="color: inherit;"><span class="MJXp-math" id="MJXp-Span-1"><span class="MJXp-mstyle" id="MJXp-Span-2"><span class="MJXp-msubsup" id="MJXp-Span-3"><span class="MJXp-mrow" id="MJXp-Span-4" style="margin-right: 0.05em;"><span class="MJXp-mi MJXp-italic" id="MJXp-Span-5">C</span><span class="MJXp-mi MJXp-italic" id="MJXp-Span-6">H</span></span><span class="MJXp-mrow MJXp-script" id="MJXp-Span-7" style="vertical-align: -0.4em;"><span class="MJXp-mn" id="MJXp-Span-8">3</span></span></span><span class="MJXp-msubsup" id="MJXp-Span-9"><span class="MJXp-mrow" id="MJXp-Span-10" style="margin-right: 0.05em;"><span class="MJXp-mi MJXp-italic" id="MJXp-Span-11">N</span><span class="MJXp-mi MJXp-italic" id="MJXp-Span-12">H</span></span><span class="MJXp-mrow MJXp-script" id="MJXp-Span-13" style="vertical-align: -0.4em;"><span class="MJXp-mn" id="MJXp-Span-14">2</span></span></span></span></span></span><script type="math/tex" id="MathJax-Element-1">\Large {CH}_{3} {NH}_{2}</script> tác dụng vừa đủ với dung dịch $