If $1 \ M$ and $2.5 \ L$ $NaOH$ solution is mixed with another $0.5 \ M$ and $3 \ L$ $NaOH$ solution,then the molarity of the resultant solution will be $........ \ M$.

$200 \ g$ of $20 \% \text{ } w/w$ urea solution is mixed with $400 \ g$ of $40 \% \text{ } w/w$ urea solution. What is the weight percentage $(w/w \%)$ of the resultant solution (in $.33$)?

The density of $2 \ M \ MgBr_2$ solution is $1.2 \ g/mL$. Then the molality of the solution is ........ $m$.

$A$ $5.2$ molal aqueous solution of methyl alcohol,$CH_3OH$,is supplied. What is the mole fraction of methyl alcohol in the solution?

The solutions $A$ and $B$ are $0.1 \ M$ and $0.2 \ M$ in a substance. If $100 \ mL$ of $A$ are mixed with $25 \ mL$ of $B$ and there is no change in volume,then the final molarity of the solution is ......... $M$.

$3.0\, g$ of oxalic acid $[(CO_2H)_2 \cdot 2H_2O]$ is dissolved in a solvent to prepare a $250\, mL$ solution. The density of the solution is $1.9\, g/mL$. The molality and normality of the solution,respectively,are closest to