Which gases are released when aluminum reacts with concentrated $HCl$ and concentrated $NaOH$ respectively?

If a straight line perpendicular to $2x - 3y + 7 = 0$ forms a triangle with the coordinate axes whose area is $3 \text{ sq. units}$,then the equation of the straight line is:

Charges of $2 \mu C$ and $-3 \mu C$ are placed at two points $A$ and $B$ separated by $1 \ m$. The distance of the point from $A$,where the net potential is zero,is (in $m$)

$50 \, g$ of ice at $0^{\circ} C$ is dropped into a calorimeter containing $100 \, g$ of water at $30^{\circ} C$. If the thermal capacity of the calorimeter is zero,then the amount of ice left in the mixture at equilibrium is .......... $g$.

For all values of $a$ and $b$,the line $(a+2b)x + (a-b)y + (a+5b) = 0$ passes through a fixed point. Find that point.

Which scientist is associated with the term 'Nuclein'?