The number of non-ionisable protons present in the product B obtained from the following reactions is__.
C2H5OH+PCl3→C2H5Cl+A
A+PCl3→B
PCl3 + C2H5OH → C2H5Cl + H3PO3
(A)
H3PO3 + PCl3→ H4P2O5
(A) (B)
Structure of H4P2O5

Total 2 non-ionizable protons are present.
The correct order of the rate of reaction of the following reactants with nucleophile by \( \mathrm{S_N1} \) mechanism is:
(Given: Structures I and II are rigid) 
| LIST I | LIST II | ||
|---|---|---|---|
| A | Lyman | I | Near IR |
| B | Balmer | II | Far IR |
| C | Paschen | III | Visible |
| D | p-fund | IV | UV |
In the given figure, the blocks $A$, $B$ and $C$ weigh $4\,\text{kg}$, $6\,\text{kg}$ and $8\,\text{kg}$ respectively. The coefficient of sliding friction between any two surfaces is $0.5$. The force $\vec{F}$ required to slide the block $C$ with constant speed is ___ N.
(Given: $g = 10\,\text{m s}^{-2}$) 
Two circular discs of radius \(10\) cm each are joined at their centres by a rod, as shown in the figure. The length of the rod is \(30\) cm and its mass is \(600\) g. The mass of each disc is also \(600\) g. If the applied torque between the two discs is \(43\times10^{-7}\) dyne·cm, then the angular acceleration of the system about the given axis \(AB\) is ________ rad s\(^{-2}\).

SN1 reaction mechanism takes place by following three steps –
The SN2 reaction mechanism involves the nucleophilic substitution reaction of the leaving group (which generally consists of halide groups or other electron-withdrawing groups) with a nucleophile in a given organic compound.
The mechanism of an electrophilic aromatic substitution reaction contains three main components which are:
The electrophilic substitution reaction mechanism is composed of three steps, which will be discussed more below.