# The normality of $0.3\;M$ phosphorous acid $(H_3P0_3)$ is

$(a)\;0.1 \\ (b)\;0.9 \\(c)\;0.3 \\(d)\;0.6$

$H_3PO_3$ is a dibasic acid . So, $0.3\;M$.
$H_3P0_3$ will be $2 \times 0.3 \;N,\;H_3P0_3$
ie it is $0.6\;N$ or its normality is $0.6$
Hence d is the correct answer.