Which of the following types of intercellular junctions helps in the passage of small molecules and ions?

Which of the following substances is used in gunpowder?

If $\alpha = \frac{5}{2! 3} + \frac{5 \cdot 7}{3! 3^2} + \frac{5 \cdot 7 \cdot 9}{4! 3^3} + \ldots$,then $\alpha^2 + 4\alpha$ is equal to

Number of moles of $MnO_4^-$ required to oxidize one mole of ferrous oxalate completely in acidic medium will be .............. $moles$.

Nuclear fusion is common to the pair:

The enthalpy of formation of ammonia is $-46.0 \, kJ \, mol^{-1}$. The enthalpy change for the reaction $2NH_{3(g)} \longrightarrow N_{2(g)} + 3H_{2(g)}$ is ..... $kJ \, mol^{-1}$.