The correct option is(A): monobasic acid and weak Lewis acid.
H3BO3 (Boric Acid):
Monobasic Acid: Boric acid is a weak monobasic acid. This means it can donate one hydrogen ion (H+) per molecule when it reacts with water. However, its acidity is relatively weak compared to strong acids. It forms a relatively small number of hydrogen ions in solution.
Weak Lewis Acid: Boric acid is considered a weak Lewis acid. A Lewis acid is a species that can accept an electron pair from a Lewis base during a chemical reaction. In the case of boric acid, it has an empty p-orbital on the boron atom, which allows it to accept an electron pair from a Lewis base.
A temperature difference can generate e.m.f. in some materials. Let $ S $ be the e.m.f. produced per unit temperature difference between the ends of a wire, $ \sigma $ the electrical conductivity and $ \kappa $ the thermal conductivity of the material of the wire. Taking $ M, L, T, I $ and $ K $ as dimensions of mass, length, time, current and temperature, respectively, the dimensional formula of the quantity $ Z = \frac{S^2 \sigma}{\kappa} $ is:
Let $ a_0, a_1, ..., a_{23} $ be real numbers such that $$ \left(1 + \frac{2}{5}x \right)^{23} = \sum_{i=0}^{23} a_i x^i $$ for every real number $ x $. Let $ a_r $ be the largest among the numbers $ a_j $ for $ 0 \leq j \leq 23 $. Then the value of $ r $ is ________.
Let $ y(x) $ be the solution of the differential equation $$ x^2 \frac{dy}{dx} + xy = x^2 + y^2, \quad x > \frac{1}{e}, $$ satisfying $ y(1) = 0 $. Then the value of $ 2 \cdot \frac{(y(e))^2}{y(e^2)} $ is ________.