JEE Mains · Chemistry · STD 12 - 3. Chemical kinetics
A radioactive element has a half life of \(200\, days.\) The percentage of original activity remaining after \(83\, days\) is \(....\) (Nearest integer) (Given : antilog \(0.125=1.333\), antilog \(0.693=\) 4.93)
- A \(91\)
- B \(85\)
- C \(75\)
- D \(750\)
Answer & Solution
Correct Answer
(C) \(75\)
Step-by-step Solution
Detailed explanation
\(t =\frac{ t _{1 / 2}}{0.3} \log \frac{[ A ]_{0}}{[ A ]_{ t }}\) \(83=\frac{200}{0.3} \log \frac{[ A ]_{0}}{[ A ]_{ t }}\) \(0.125=\log \frac{[ A ]_{0}}{[ A ]_{ t }}\) \(\frac{[ A ]_{0}}{[ A ]_{ t }}=1.333 \cong \frac{4}{3}\)…
See the Complete Solution
Get step-by-step explanations for this and 2.5 Lakh+ more JEE, NEET & CET questions.
- Unlock all solutions
- Practice the full chapter
- Track accuracy across PYQs
4.8 rated on Google Play · 14,000+ reviews
More questions from Chemistry
- An ideal gas undergoes isothermal expansion at constant pressure. During the processJEE Mains 2017 Hard
- The decreasing order of electrical conductivity of the following aqueous solutions is
\(0.1\, M\) Formic acid \((a)\)
\(0.1\, M\) Acetic acid \((b)\)
\(0.1\, M\) Benzoic acid \((c)\)JEE Mains 2019 Hard - Given below are two statements: one is labelled as Assertion \((A)\) and the other is labelled as Reason \((R)\).
Assertion \((A)\) : Both rhombic and monoclinic sulphur exist as \(S_5\) while oxygen exists as \(O_2\). Reason \((R)\) : Oxygen forms \(\mathrm{p} \pi-\mathrm{p} \pi\) multiple bonds with itself and other elements having small size and high electronegativity like \(\mathrm{C}, \mathrm{N}\), which is not possible for sulphur. In the light of the above statements, choose the most appropriate answer from the options given below :JEE Mains 2024 Medium - 20 mL of 2 M NaOH solution is added to 400 mL of 0.5 M NaOH solution. The final concentration of the solution is _______ \(\times 10^{-2} \mathrm{M}\). (Nearest integer)JEE Mains 2025 Medium
- The correct order of \(pK _{ a }\) values for the following compounds is:
JEE Mains 2023 Hard - Given below are two statements :
Statement \((I)\) : Aqueous solution of ammonium carbonate is basic.
Statement \((II)\) : Acidic/basic nature of salt solution of a salt of weak acid and weak base depends on \(\mathrm{K}_{\mathrm{a}}\) and \(K_b\) value of acid and the base forming it.
In the light of the above statements, choose the most appropriate answer from the options given below :JEE Mains 2024 Hard
More PYQs from JEE Mains
- A mixture of hydrogen and oxygen has volume \(2000 \; cm ^{3}\), temperature \(300 \; K\), pressure \(100 \; kPa\) and mass \(0.76 \; g\) The ratio of number of moles of hydrogen to number of moles of oxygen in the mixture will beJEE Mains 2022 Medium
- Two moles of benzaldehyde and one mole of acetone under alkaline conditions using aqueous \(\mathrm{NaOH}\) after heating gives \(x\) as the major product. The number of \(\pi\) bonds in the product \(x\) is _______.JEE Mains 2024 Medium
- If \(\sum_{r=0}^5 \frac{{ }^{11} C_{2r+1}}{2 r+2}=\frac{\mathrm{m}}{\mathrm{n}}, \operatorname{gcd}(\mathrm{m}, \mathrm{n})=1\), then \(\mathrm{m}-\mathrm{n}\) is equal to _______JEE Mains 2025 Hard
- One side of an equilateral prism is painted by a transparent material of refractive index \(n_2\). The refractive index of prism is \(1.6\). The minimum value of \(n_2\) required for total internal reflection from painted face is _______.
JEE Mains 2026 Hard - The output characteristics of a transistor is shown in the figure. When \(V_{C E}\) is \(10\, V\) and \(I_{ C }=4.0\, mA ,\) then value of \(\beta_{ ac }\) is
JEE Mains 2020 Medium - In an experiment, the resistance of a material is plotted as a function of temperature (in some range). As shown in the figure, it is a straight line. One may conclude that:
JEE Mains 2019 Hard