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The reaction that does NOT take place in a blast furnace between 900 K to 1500 K temperature range during extraction of iron is:
Fe₂O₃ → FeO occurs in the upper, cooler part of the furnace (≈500–800 K), not in the 900–1500 K zone.
Which is the correct relation between change in enthalpy and change in internal energy?
$\Delta H = \Delta U + p\Delta V = \Delta U + \Delta n_g RT$.
Consider the following compounds/species:
i.
ii.
iii.
iv.
v.
vi.
vii.
The number of compounds/species which obey Huckel's rule is:
Aromatic (4n+2): naphthalene (10π), cyclopentadienyl anion (6π), cyclopropenyl cation (2π), anthracene (14π) → 4. Cyclobutadiene & cyclopropenyl anion are antiaromatic; cyclooctatetraene is non-planar.
The equilibrium concentrations of the species in the reaction $A + B \rightleftharpoons C + D$ are $2, 3, 10$ and $6\ \text{mol L}^{-1}$, respectively at 300 K. $\Delta G^\circ$ for the reaction is ($R = 2\ \text{cal mol}^{-1} \text{K}^{-1}$):
$K_c = \dfrac{10\times 6}{2\times 3} = 10$. $\Delta G^\circ = -RT\ln K_c = -2(300)(2.303) = -1381.8\ \text{cal}$.
Which of the following statements are INCORRECT?
A. All the transition metals except scandium form MO oxides which are ionic. B. The highest oxidation number corresponding to the group number in transition metal oxides is attained in Sc₂O₃ to Mn₂O₇. C. Basic character increases from V₂O₃ to V₂O₄ to V₂O₅. D. V₂O₄ dissolves in acids to give VO₄³⁻ salts. E. CrO is basic but Cr₂O₃ is amphoteric.
C wrong (basicity decreases as oxidation number rises). D wrong (V₂O₄ + acid gives $VO^{2+}$, not VO₄³⁻).
Movement and accumulation of ions across a membrane against their concentration gradient can be explained by:
Active transport uses ATP to move solutes against the gradient.
How many ATP and NADPH₂ are required for the synthesis of one molecule of Glucose during Calvin cycle?
Per glucose: 18 ATP + 12 NADPH (6 turns × 3 ATP and 2 NADPH per turn).
Which micronutrient is required for splitting of water molecule during photosynthesis?
The OEC of PSII has a Mn₄CaO₅ cluster that oxidises water.
Given below are two statements:
Statement I: Endarch and exarch are the terms often used for describing the position of secondary xylem in the plant body.
Statement II: Exarch condition is the most common feature of the root system.
In the light of the above statements, choose the correct answer:
Endarch in stems (protoxylem inside), exarch in roots (protoxylem outside).
Assertion A: Late wood has fewer xylary elements with narrow vessels. Reason R: Cambium is less active in winters.
Lower cambial activity in winter produces narrower, fewer xylem vessels.
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