I am new to LaTeX and trying to draw a table. I have followed a couple of guides and found solutions to problems I was having on here but I can't find anything to help me remove the white lines I have running through my table and to the left of the second row.
Please can someone help me?
\documentclass[paper=a4, fontsize=11pt]{scrartcl}
\usepackage{multirow, booktabs}
\usepackage{array}
\usepackage[table]{xcolor}
\newcolumntype{x}[1]{%
>{\centering\hspace{0pt}}p{#1}}%
\definecolor{myblue}{RGB}{122, 140, 213}
\renewcommand{\arraystretch}{1.5}
\begin{center}
\begin{tabular}{|x{3cm}|x{3.5cm}|x{3.5cm}| }\hline
\rowcolor{myblue!50} & \multicolumn{2}{|c|}{Concentration of Sodium Hydroxide Added /M} \\ \cmidrule{2-3}
\rowcolor{myblue!50} \multirow{-2}{*}{Sample Number} & Drop 1 (left) & Drop 2 (Right)\tabularnewline\hline
1 & 0.01 M & 1.00 M \tabularnewline\hline
2 & 0.05 M & 0.10 M \tabularnewline\hline
3 & 0.10 M & 0.01 M \tabularnewline\hline
4 & 0.50 M & 0.05 M \tabularnewline\hline
5 & 1.00 M & 0.50 M \tabularnewline\hline
\end{tabular}
\end{center}