JEE Advanced 2019 · Paper 2

The cyanide process of gold extraction involves leaching out gold from its ore with CN⁻ in the presence of Q in water to form R. Subsequently, R is treated with T to obtain Au and Z. Choose the correct option(s)

1. AQ is O₂
2. BT is Zn
3. CZ is [Zn(CN)₄]²⁻
4. DR is [Au(CN)₄]⁻

With reference to aqua regia, choose the correct option(s)

1. AAqua regia is prepared by mixing conc. HCl and conc. HNO₃ in 3:1 (v/v) ratio
2. BReaction of gold with aqua regia produces an anion having Au in +3 oxidation state
3. CReaction of gold with aqua regia produces NO₂ in the absence of air
4. DThe yellow colour of aqua regia is due to the presence of NOCl and Cl₂

Consider the following reactions (unbalanced) Zn + hot conc. H₂SO₄ → G + R + X Zn + conc. NaOH → T + Q G + H₂S + NH₄OH → Z (a precipitate) + X + Y Choose the correct option(s)

1. AZ is dirty white in colour
2. BThe oxidation state of Zn in T is +1
3. CR is a V-shaped molecule
4. DBond order of Q is 1 in its ground state

The ground state energy of hydrogen atom is −13.6 eV. Consider an electronic state Ψ of He⁺ whose energy, azimuthal quantum number and magnetic quantum number are −3.4 eV, 2 and 0, respectively. Which of the following statement(s) is(are) true for the state Ψ?

1. AIt is a 4d state
2. BIt has 2 angular nodes
3. CIt has 3 radial nodes
4. DThe nuclear charge experienced by the electron in this state is less than 2e, where e is the magnitude of the electronic charge

Choose the correct option(s) from the following

1. ANatural rubber is polyisoprene containing trans alkene units
2. BNylon-6 has amide linkages
3. CTeflon is prepared by heating tetrafluoroethene in presence of a persulphate catalyst at high pressure
4. DCellulose has only α-D-glucose units that are joined by glycosidic linkages