The Phthalein test is a characteristic test for which of the following?

Which pair of oxides is acidic in nature?

An object is projected with a velocity of $20 \ m/s$ making an angle of $45^{\circ}$ with the horizontal. The equation for the trajectory is $h = Ax - Bx^2$,where $h$ is the height,$x$ is the horizontal distance,and $A$ and $B$ are constants. The ratio $A:B$ is $(g = 10 \ m/s^2)$.

Two nuclei have their mass numbers in the ratio of $1 : 3.$ The ratio of their nuclear densities would be

$\lim _{x \rightarrow 0} \frac{(1-e^x) \sin x}{x^2+x^3}$ is equal to

Compound $PdCl_4 \cdot 6H_2O$ is a hydrated complex; $1 \, m$ aqueous solution of it has a freezing point of $269.28 \, K$. Assuming $100 \%$ ionization of the complex,calculate the molecular formula of the complex ($K_f$ for water $= 1.86 \, K \, kg \, mol^{-1}$,freezing point of pure water $= 273.15 \, K$).