| LIST I Elements | LIST II Colour imparted to the flame | ||
| A | K | 1 | Brick Red |
| B | Ca | 2 | Violet |
| C | Sr | 3 | Apple Green |
| D | Ba | 4 | Crimson Red |
Correct answer is (d) A-II, B-I, C-IV, D-III

The flame test is used to identify elements based on the characteristic colors they emit when heated. The correct matching is:
Thus, the correct matching corresponds to option (4).
Method used for separation of mixture of products (B and C) obtained in the following reaction is: 
MX is a sparingly soluble salt that follows the given solubility equilibrium at 298 K.
MX(s) $\rightleftharpoons M^{+(aq) }+ X^{-}(aq)$; $K_{sp} = 10^{-10}$
If the standard reduction potential for $M^{+}(aq) + e^{-} \rightarrow M(s)$ is $(E^{\circ}_{M^{+}/M}) = 0.79$ V, then the value of the standard reduction potential for the metal/metal insoluble salt electrode $E^{\circ}_{X^{-}/MX(s)/M}$ is ____________ mV. (nearest integer)
[Given : $\frac{2.303 RT}{F} = 0.059$ V]
An infinitely long straight wire carrying current $I$ is bent in a planar shape as shown in the diagram. The radius of the circular part is $r$. The magnetic field at the centre $O$ of the circular loop is :
