| 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).
Given below are two statements. 
In the light of the above statements, choose the correct answer from the options given below:
Given below are two statements:
Statement I: Nitrogen forms oxides with +1 to +5 oxidation states due to the formation of $\mathrm{p} \pi-\mathrm{p} \pi$ bond with oxygen.
Statement II: Nitrogen does not form halides with +5 oxidation state due to the absence of d-orbital in it.
In the light of the above statements, choose the correct answer from the options given below:
0.01 mole of an organic compound (X) containing 10% hydrogen, on complete combustion, produced 0.9 g H₂O. Molar mass of (X) is ___________g mol\(^{-1}\).
If the system of equations \[ (\lambda - 1)x + (\lambda - 4)y + \lambda z = 5 \] \[ \lambda x + (\lambda - 1)y + (\lambda - 4)z = 7 \] \[ (\lambda + 1)x + (\lambda + 2)y - (\lambda + 2)z = 9 \] has infinitely many solutions, then \( \lambda^2 + \lambda \) is equal to: