Comment on the following statements.
`CH_4` does not react with oxygen at room temperture but burns when a lighted match stick is applied to the mixture.

Compound X (molecular formula C_5 H_8 O ) does not react appreciably with Lucas reagent at room temperature but gives a precipitate with amononiacal silver nitrate with excess of MeMgBr, 0.42 gm of X gives 224 ml of CH_4 at S.T.P Treatment of X with H_2 . in the presence of Pt catalyst followed by boiling with excess of HI , gives n-pentane. Suggest the structure for X and write the equations involved.

Which one of the following pairs of reactantas does not form oxygen when they react with each other ?

40 cm^(3) of methane are mixed with 100 cm^(3) of pure oxygen at room temperature and pressure. The mixture is then ignited when it burns as illustrated by the equation. Calculate the composition of the resulting mixture if it cooled to initial room temperature and pressure. [CH_(4)(g) + 2O_(2)(g) to CO_(2)(g) + 2H_(2)O(l)]

Which of the following statements is/are correct, when a mixture of NaCl and K_2Cr_2O_7 is gently warmed with concentrated H_2SO_4 ?

Which of the following statements is/are correct, when a mixture of NaCl and K_2Cr_2O_7 is gently warmed with concentrated H_2SO_4 ?

Give scientific reasons for the following statements: We feel blinded for a short while entering a dark room when coming from bright light.

Which of the following statement are correct when a mixture of Nacl and K_(2)Cr_(2)O_(7) is gently warmed with conc. H_(2)SO_(4) ?

Which of the following statement is correct when a mixture of CaCl_(2) and K_(2)Cr_(2)O_(7) is gently warmed with conc . H_(2)SO_(4) acid ?

When hydrochloric aicd is addded to cobalt and nitrate solution at room temperautre, the following reaction takes place and the reaction mixture becomes blue. On cooling the mixture it becomes pink. On the basis of this information mark the corect ansewer. underset("pink")[[Co(H_(2)O)_(6)]]^(3+)(aq)+4CI^(-)hArr underset("blue")[CoCI_(4)]^(2-)(aq)+6H_(2)O(l) (A)Δ H > 0 for the reaction (B)Δ H < 0 for the reaction (C)Δ H = 0 for the reaction (D)The sign of Δ H cannot be predicted on the basis of this information

Stomatal movements are influenced by a number of environmental factors, Which of the following statements is // are incorrect regarding this? (ii)Blue light keeps stomata open during the day pormoting the movement of K_(+) ions into guard cells. (ii) Increased CO_(2) concentraation reduces the pH of guard cells which promotes conversion of sugar into starch ultimately causing closure of stomata. (iii) Abscisic acid under stress conditions, causes repid movement of K_(+) ions into guard cells. Highly concentrated sucrose or salt solution when applied over to stomata results in stomata opening.