The correct statement(s) related to oxoacids of phosphorous is(are)

The reaction of $4$-methyloct-$1$-ene $(\mathrm{P},2.52 \mathrm{g})$ with $\mathrm{HBr}$ in the presence of ${\left({\mathrm{C}}_6{\mathrm{H}}_5\mathrm{CO}\right)}_2{\mathrm{O}}_2$ gives two isomeric bromides in a $9: 1$ ratio, with a combined yield of $50\%$. Of these, the entire amount of the primary alkyl bromide was reacted with an appropriate amount of diethylamine followed by treatment with aq. ${\mathrm{K}}_2{\mathrm{CO}}_3$ to give a non-ionic product $\mathrm{S}$ in $100\%$ Yield. The mass (in $\mathrm{mg}$ ) of $\mathrm{S}$ obtained is
[Use molar mass (in ${\mathrm{gmol}}^{-1}$ ): $\mathrm{H}=1,\mathrm{C}=12, \mathrm{N}=14,\mathrm{Br}=80$ ]

The value of \(n\) in the molecular formula \(\mathrm{Be}_n \mathrm{Al}_2 \mathrm{Si}_6 \mathrm{O}_{18}\) is

Among the electrolytes \(\mathrm{Na}_2 \mathrm{SO}_4, \mathrm{CaCl}_2 \quad \mathrm{Al}_2\left(\mathrm{SO}_4\right)_3\) and \(\mathrm{NH}_4 \mathrm{Cl}\), the most effective coagulating agent for \(\mathrm{Sb}_2 \mathrm{~S}_3\) sol is

Paragraph:
There are some deposits of nitrates and phosphates in earth's crust. Nitrates are more soluble in water. Nitrates are difficult to reduce under the laboratory conditions but microbes do it easily. Ammonia forms large number of complexes with transition metal ions. Hybridisation easily explains the ease of sigma donation capability of \(\mathrm{NH}_3\) and \(\mathrm{PH}_3\). Phosphine is a flammable gas and is prepared from white phosphorus.
Question:
Among the following, the correct statement is

Paragraph:
Chemical reactions involve interaction of atoms and molecules. A large number of atoms/molecules (approximately \(6.023 \times 10^{23}\) ) are present in a few grams of any chemical compound varying with their atomic/molecular masses. To handle such large numbers conveniently, the mole concept was introduced. This concept has implications in diverse areas such as analytical chemistry, biochemistry, electrochemistry and radiochemistry. The following example illustrates a typical case, involving chemical/electrochemical reaction, which requires a clear understanding of the mole concept.
A \(4.0\) molar aqueous solution of \(\mathrm{NaCl}\) is prepared and \(500 \mathrm{~mL}\) of this solution is electrolysed. This leads to the evolution of chlorine gas at one of electrodes (atomic mass: \(\mathrm{Na}=23, \mathrm{Hg}=200 ; 1\) faraday \(=96500\) coulombs).
Question:
The total charge (coulombs) required for complete electrolysis is

\(\mathrm{AgNO}_3(a q)\) was added to an aqueous \(\mathrm{KCl}\) solution gradually and the conductivity of the solution was measured. The plot of conductance \((\Lambda)\) versus the volume of \(\mathrm{AgNO}_3\) is

Paragraph : If the measurement errors in all the independent quantities are known, then it is possible to determine the error in any dependent quantity. This is done by the use of series expansion and truncating the expansion at the first power of the error. For example, consider the relation $z =\frac{x}{y}$. If the errors in $x, y \mathrm{a}\mathrm{n}\mathrm{d} z \mathrm{a}\mathrm{r}\mathrm{e} ∆x, ∆y \mathrm{a}\mathrm{n}\mathrm{d} ∆z$ , respectively, then

$z\pm ∆z=\frac{x\pm ∆x}{y\pm ∆y}=\frac{x}{y}\left(1\pm \frac{∆x}{x}\right){\left(1\pm \frac{∆y}{y}\right)}^{-1}$

The series expansion for ${\left(1\pm \frac{∆y}{y}\right)}^{-1}$, to first power in $∆y/y, \mathrm{i}\mathrm{s} 1\mp \left(∆y/y\right)$. The relative errors in independent variables are always added. So the error in $z$ will be

$\text{Δ}z=z\left(\frac{\text{Δ}x}{x}+\frac{\text{Δ}y}{y}\right).$
The above derivation makes the assumption that \(\Delta r / x \ll 1, \Delta y / y < 1\). Therefore, the higher powers of these quantities are neglected.
Question : Consider the ratio \(r=\frac{(1-a)}{(1+a)}\) to be determined by measuring a dimensionless quantity a If the error in the measurement of a is \(\Delta a(\frac{\Delta a}{a}<<1)\), then what is the error \(\Delta r\) in determining \(r\) ?

Adsorption of phenol from its aqueous solution on to fly ash obeys Freundlich isotherm. At a given temperature, from \(10 \mathrm{mg} \mathrm{g}^{-1}\) and \(16 \mathrm{mg} \mathrm{g}^{-1}\) aqueous phenol solutions, the concentrations of adsorbed phenol are measured to be \(4 \mathrm{mg} \mathrm{g}^{-1}\) and \(10 \mathrm{mg} \mathrm{g}^{-1}\), respectively. At this temperature, the concentration (in \(\mathrm{mg} \mathrm{g}^{-1}\) ) of adsorbed phenol from \(20 \mathrm{mg} \mathrm{g}^{-1}\) aqueous solution of phenol will be \(\qquad\) .
Use : \(\log _{10} 2=0.3\)

Native silver metal forms a water soluble complex with a dilute aqueous solution of \(\mathrm{NaCN}\) in the presence of

\(\mathrm{MgSO}_4\) on reaction with \(\mathrm{NH}_4 \mathrm{OH}\) and \(\mathrm{Na}_2 \mathrm{HPO}_4\) forms a white crystalline precipitate. What is its formula?

A solution is prepared by mixing $0.01\mathrm{mol}$ each of ${\mathrm{H}}_2{\mathrm{CO}}_3,{\mathrm{NaHCO}}_3,{\mathrm{Na}}_2{\mathrm{CO}}_3$, and $\mathrm{NaOH}$ in \(100 \mathrm{~mL}\) of water. $\mathrm{pH}$ of the resulting solution is
[Given: ${\mathrm{pK}}_{{\mathrm{a}}_1}$ and ${\mathrm{pK}}_{{\mathrm{a}}_2}$ of ${\mathrm{H}}_2{\mathrm{CO}}_3$ are $6.37$ and $10.32$, respectively. $\log 2=0.30$]

What is the order of basicity among the following compounds?