# 25ml of 3.0M $HNO_3$ are mixed with 75ml of 4.0M $HNO_3$.If the volumes are additive,the molarity of the final mixture would be :

$(a)\;3.25M\qquad(b)\;4.0M\qquad(c)\;3.75M\qquad(d)\;3.50M$

M-Mol of $HNO_3$=$25\times 3=75$
M-Mol of $HNO_3$=$75\times 4=300$
$\therefore$Total M-mol=375
This 375=$M\times 100$
$\therefore M=3.75$
Hence (c) is the correct answer.