Question Library

In unstable equilibrium, when the cone is disturbed, it tends to fall further from its equilibrium position, leading to a decrease in height and thus an increase in potential energy.

\omega = 2\piF = 2\pi \times 2 = 4\pirad\(^{-1}\) Centripetal force = mr\omega\(^2\) ⇒ 0.5 \times 2 \times (4\pi)\(^2\) ⇒ 157.75N Approximately = 158N.

Stable equilibrium brings about increase in potential energy as the height rises after displacement.

Meter rule has a reading accuracy of 0.5mm or 0.05cm, thus measurement is M \pm 0.05cm i.e 2.00, 2.05, 2.50, 2.55 etc. The reading that cannot be read is 2.56cm.

This is the correct graph. The graph is volume against temperature where temperature is in Celsius.

This is the correct graph. The graph is volume against temperature where temperature is in Celsius.

secondary alkanols (alcohols) can be oxidised to alkanones (ketones)

A hydrocarbon that will produce a red precipitate when reacted with an aqueous solution of copper(I) chloride is an alkyne. More specifically, an alkyne with a terminal triple bond, like ethyne (acetylene), will react to form a red precipitate of copper(I) acetylide. The most reactive alkynes are those where the triple bond is at the end of the carbon chain (terminal triple bond).

While naming the IUPAC nomenclature of hydrocarbon compounds, we usually start with the naming from the rare i.e the functional group from the right hand side. Consider CH\(_3\)CH\(_2\)COOCH\(_2\)CH\(_3\), this is an ester obtained from two compounds propanoic acid and ethanol. On splitting CH\(_3\)CH\(_2\)COOCH\(_2\)CH\(_3\), we have CH\(_3\)CH\(_2\)COO / CH\(_2\)CH\(_3\) dividing the compound into two; CH\(_3\)CH\(_2\)COO - Propanoate and CH\(_2\)CH\(_3\) - ethyl So while naming as mentioned earlier on, we start the naming from the rare(RHS), and then the other(LHS). Thus, the name of the compound is; ethylpropanoate.

Only hydrocarbons containing an aldehyde group (RCHO) or a terminal alkyne (R-C≡C-H) will react with Tollens' reagent, leading to a silver mirror formation or a white precipitate, respectively. Aldehydes are oxidized by Tollens' reagent (ammoniacal silver nitrate solution) to form carboxylic acids, while the silver ions (Ag+) are reduced to metallic silver (Ag), which deposits as a silver mirror on the walls of the test tube. Terminal alkynes react with Tollens' reagent, producing a white precipitate of silver acetylide.

The IUPAC name of the compound CF\(_3\)CHBrCl is 2-bromo-2-chloro-1,1,1-trifluoroethane. This compound is famously known by its non-proprietary name, Halothane, and was widely used as an inhalation anesthetic. Breakdown of the Name To arrive at the correct IUPAC name, we follow standard nomenclature rules: Identify the Parent Chain: The longest carbon chain contains two carbons, making the parent alkane ethane. Numbering the Chain: We number the carbons to give the substituents the lowest possible locants. If we start from the carbon with the three fluorine atoms, the locants are (1,1,1,2,2). If we start from the carbon with bromine and chlorine, the locants are (1,1,2,2,2). In this case, both directions yield the same set of locants. However, IUPAC rules state that if numbering is equivalent from both ends, we give the lower number to the substituent that comes first alphabetically. Since Bromo and Chloro come before Fluoro, the carbon attached to Br and Cl is designated as Carbon-2 (wait, let me re-check that logic). Actually, per the lowest locant set rule, we prioritize the side with more substituents to keep the numbers lower. The carbon with three fluorines gets "1" so the set is (1,1,1,2,2) rather than (1,2,2,2,2). Correction: In the specific case of Halothane, the standard IUPAC assignment labels the carbon with the three fluorines as C1, resulting in 2-bromo-2-chloro-1,1,1-trifluoroethane

No expanded working has been attached for this question yet. The verified answer is Option D.

The chemical reaction between magnesium ribbon and oxygen is a combustion reaction that produces magnesium oxide (MgO). Burning Magnesium ribbon in air removes oxygen, because as Magnesium burns in air, it reacts with oxygen in the air to form Magnesium oxide. The chemical equation for this reaction is 2Mg(s)+O\(_2\)(g) → 2MgO(s)

The best starting material for the preparation of oxygen through heating trioxonitrate(V) (nitrates) would involve a metal that facilitates the decomposition of the nitrate to produce oxygen, coincidentally, Pb (Lead) falls into that category. Lead(II) nitrate (Pb(NO\(_3\))\(_2\)) decomposes upon heating to produce oxygen, nitrogen dioxide, and lead(II) oxide. This reaction is often used in laboratory settings to generate oxygen. 2Pb(NO\(_3\))\(_2\) → 2PbO + 4NO\(_2\) + O\(_2\) This makes lead (Pb) a suitable choice for generating oxygen from nitrates.

No expanded working has been attached for this question yet. The verified answer is Option C.