An NMR task:

The First NMR:

The Second NMR:

The Third NMR:

And the TikZ Source Code:

\documentclass[a4paper,landscape]{article}

\usepackage[english]{babel}
\usepackage[utf8x]{inputenc}
\usepackage{amsmath}
\usepackage{graphicx}
\usepackage[colorinlistoftodos]{todonotes}
\usepackage{tikz}
\usetikzlibrary{shadows}
\usepackage{chemfig}

\begin{document}
\pagestyle{empty}
%% A Little NMR Quiz


%% Some Macro definitions
\def\peaka{10}
\def\peakb{7.88}
\def\inta{5.31}
\def\peakc{7.876}
\def\intc{6.11}
\def\peakd{7.873}
\def\intd{2.92}
\def\peake{7.86}
\def\inte{2.4}
\def\peakf{7.858}
\def\intf{7.0}
\def\peakg{7.855}
\def\intg{6.75}

\begin{tikzpicture}
\node[ draw=blue,rounded corners,fill=blue!50!green,drop shadow ] (0,0) {
\begin{minipage}{.7\textwidth}
Find the right NMR spectra for the following three compounds:\\
~\\
\chemfig{[:30]*6(-=-=-(-[::-60](-[::-45]H)=[::45]O)=)}\\
~\\
\chemfig{-[::30]-[::-60](=[::-60]O)-[::60]O-[::-60]-[::60]}
\end{minipage}};\\
~\\
~\\
~\\
\chemfig{-[::45](=[::45]O)-[::-90]}\\
\end{tikzpicture}

\begin{tikzpicture}[xscale=-1]

%% benzaldehyde

%% Background stuff
\draw[fill=green!50!blue!50!white,opacity=0.7,rounded corners,drop shadow]%%
    (-2,-2)rectangle(13,12);

%% Some Styling
\tikzstyle{axesStyle}=[very thick,->,>={stealth}]
\tikzstyle{peakStyle}=[thick]

%% Coordinate Stuff
\coordinate (P0) at (0,0);
\coordinate (Px) at (12,0);
\coordinate (Py) at (0,11);

%% Draw the axes
\draw[axesStyle](P0) -- (Py);
\draw[axesStyle](P0) -- (Px);

%% Labeling of the axes
\node[rotate=-90] at (-0.3,5.5) {Intensity};
\node at (6,-0.7) {Shift[ppm]};

%% Draw the Peaks
\draw[peakStyle](\peaka,10)--(\peaka,0);
\draw[peakStyle](\peakb,\inta)--(\peakb,0);
\draw[peakStyle](\peakc,\intc)--(\peakc,0);
\draw[peakStyle](\peakd,\intd)--(\peakd,0);
\draw[peakStyle](\peake,\inte)--(\peake,0);
\draw[peakStyle](\peakf,\intf)--(\peakf,0);
\draw[peakStyle](\peakg,\intg)--(\peakg,0);
\draw[peakStyle](7.51,6.54)--(7.51,0);
\draw[peakStyle](7.53,4.9)--(7.53,0);

%% 
\foreach \x in {0,1,2,...,11}
{
    \node at (\x,-0.3) {\x};
    \draw[very thick](\x,0.2)--(\x,0);
    \draw(\x+0.5,0.15)--(\x+0.5,0);
}
\end{tikzpicture}

\def\peakone{4.132}
\def\intone{5}
\def\peaktwo{2.32}
\def\inttwo{5}
\def\peakthree{1.26}
\def\intthree{9}
\def\peakfour{1.14}
\def\intfour{9}

\begin{tikzpicture}[xscale=-1]
%% Ethyl propionate

%% Background stuff
\draw[fill=green!50!blue!50!white,opacity=0.7,rounded corners,drop shadow]%%
    (-2,-2)rectangle(13,12);

%% Some Styling
\tikzstyle{axesStyle}=[very thick,->,>={stealth}]
\tikzstyle{peakStyle}=[thick]

%% Coordinate Stuff
\coordinate (P0) at (0,0);
\coordinate (Px) at (12,0);
\coordinate (Py) at (0,11);

%% Draw the axes
\draw[axesStyle](P0) -- (Py);
\draw[axesStyle](P0) -- (Px);

%% Labeling of the axes
\node[rotate=-90] at (-0.3,5.5) {Intensity};
\node at (6,-0.7) {Shift[ppm]};

\draw[peakStyle] (\peakone,\intone) -- (\peakone,0);
\draw[peakStyle] (\peaktwo,\inttwo) -- (\peaktwo,0);
\draw[peakStyle] (\peakthree,\intthree) -- (\peakthree,0);
\draw[peakStyle] (\peakfour,\intfour) -- (\peakfour,0);
%% 
\foreach \x in {0,1,2,...,11}
{
    \node at (\x,-0.3) {\x};
    \draw[very thick](\x,0.2)--(\x,0);
    \draw(\x+0.5,0.15)--(\x+0.5,0);
}


\end{tikzpicture}


\begin{tikzpicture}[xscale=-1]
%% acetone

%% Background stuff
\draw[fill=green!50!blue!50!white,opacity=0.7,rounded corners,drop shadow]%%
    (-2,-2)rectangle(13,12);

%% Some Styling
\tikzstyle{axesStyle}=[very thick,->,>={stealth}]
\tikzstyle{peakStyle}=[thick]

%% Coordinate Stuff
\coordinate (P0) at (0,0);
\coordinate (Px) at (12,0);
\coordinate (Py) at (0,11);

%% Draw the axes
\draw[axesStyle](P0) -- (Py);
\draw[axesStyle](P0) -- (Px);

%% Labeling of the axes
\node[rotate=-90] at (-0.3,5.5) {Intensity};
\node at (6,-0.7) {Shift[ppm]};

\draw[peakStyle] (2.2,7) -- (2.2,0);

%% 
\foreach \x in {0,1,2,...,11}
{
    \node at (\x,-0.3) {\x};
    \draw[very thick](\x,0.2)--(\x,0);
    \draw(\x+0.5,0.15)--(\x+0.5,0);
}


\end{tikzpicture}



\end{document}