Pollen grains that would easily germinate on stigma are found to germinate in vitro, only when 10-200 p p m of boric acid is added. This suggest that

Which of the following statements is not correct 1. Insects that consume pollen or nectar without bringing about pollination are called pollen/nectar robbers 2. Pollen germination and pollen tube growth are regulated by chemical components of pollen interacting with those of the pistil 3. Some reptiles have also been reported as pollinators in some plant species 4. Pollen grains of many species can germinate on the stigma of a flower, but only one pollen tube of the same species grows into the style

Distinguish between unisexual and bisexual flowers giving one example of each. Draw a neat diagram showing fertilisation in a flower and label: a] Pollen tube b] Male germ cell c] Female germ cell, on it. OR Draw the diagram showing the germination of pollen on stigma and label the part on which pollination takes place. Answer the following questions based on diagram given aside. i] Name the part marked 'P. in the diagram. ii] How does 'P. reach part 'B'? iii] State the importance of the part 'C'. iv] What happens to the part marked 'D' after fertilisation is over? Mention the role of gamete and zygote in sexually reproducing organisms.

Read the passage given below and answer the question: Industrially widely applied esterification reactions are commonly catalysed using mineral liquid acids, such as sulphuric acid and p-toluenesulphonic acid. The catalytic activity of homogeneous catalysts is high. They suffer, however, from several drawbacks, such as their corrosive nature, the existence of side reactions, and the fact that the catalyst cannot be easily separated from the reaction mixture. The use of solid acid catalysts offers an alternative and has received a lot of attention in the past years. Solid acid catalysts are not corrosive and, coated onto a support, they can be easily reused. Examples of solid acid catalysts used in esterification reactions include ion-exchange resins, zeolites and superacids like sulphated zirconia and niobium acid. Ion-exchange resins are the most common heterogeneous catalysts used and have proven to be effective in liquid phase esterification and etherification reactions. Because of their selective adsorption of reactants and swelling nature, these resins not only catalyse the esterification reaction but also affect the equilibrium conversion. Shortcomings include insufficient thermal resistance, which limits the reaction temperature to 120^(@)C , preventing widespread use in industry. Zeolites, like Y, X, BEA, ZSM-5 and MCM 41 offer an interesting alternative and have proven to be efficient catalysts for esterification reactions. Zeolites have found wide application in oil refining, petrochemistry and in the production of fine chemicals. Their success is based on the possibility to prepare zeolites with strong Brønsted acidity that can be controlled within a certain range, combined with a good resistance to high reaction temperatures. In this study, the activity of various commercial available solid acid catalysts is assessed with respect to the esterification of acetic acid with butanol. The ion-exchange resins Amberlyst 15 and Smopex-101, the acid zeolites H-ZSM-5, H-MOR, H-BETA and H-USY, and the solid superacids sulphated zirconia and niobium acid are selected. Comparative esterification experiments have been carried out using the homogeneous catalysts sulphuric acid, p toluenesulphuric acid and a heteropolyacid (HPA). The weight-based activity of the heterogeneous catalysts tested is maximum for Smopex 101. The following table gives the activity of different catalysts in the esterification reaction between acetic acid and butanol at 75^(@)C . Here: k_(obs) : observed reaction rate constant ( m^(3) mol^(-1)s^(-1) ) kc catalysed reaction rate constant ( m^(3)mol^(-1) g_(cat)^(-1)s^(-1) ) Please note: k c = k obs/ amount (in g) (source: PETERS, T., BENES, N., HOLMEN, A., & KEURENTJES, J. (2006). Comparison of commercial solid acid catalysts for the esterification of acetic acid with butanol. Applied Catalysis A: General, 297(2), 182-188. doi:10.1016/j.apcata.2005.09.00) Catalysts used in oil refining industry are:

Read the passage given below and answer the question: Industrially widely applied esterification reactions are commonly catalysed using mineral liquid acids, such as sulphuric acid and p-toluenesulphonic acid. The catalytic activity of homogeneous catalysts is high. They suffer, however, from several drawbacks, such as their corrosive nature, the existence of side reactions, and the fact that the catalyst cannot be easily separated from the reaction mixture. The use of solid acid catalysts offers an alternative and has received a lot of attention in the past years. Solid acid catalysts are not corrosive and, coated onto a support, they can be easily reused. Examples of solid acid catalysts used in esterification reactions include ion-exchange resins, zeolites and superacids like sulphated zirconia and niobium acid. Ion-exchange resins are the most common heterogeneous catalysts used and have proven to be effective in liquid phase esterification and etherification reactions. Because of their selective adsorption of reactants and swelling nature, these resins not only catalyse the esterification reaction but also affect the equilibrium conversion. Shortcomings include insufficient thermal resistance, which limits the reaction temperature to 120^(@)C , preventing widespread use in industry. Zeolites, like Y, X, BEA, ZSM-5 and MCM 41 offer an interesting alternative and have proven to be efficient catalysts for esterification reactions. Zeolites have found wide application in oil refining, petrochemistry and in the production of fine chemicals. Their success is based on the possibility to prepare zeolites with strong Brønsted acidity that can be controlled within a certain range, combined with a good resistance to high reaction temperatures. In this study, the activity of various commercial available solid acid catalysts is assessed with respect to the esterification of acetic acid with butanol. The ion-exchange resins Amberlyst 15 and Smopex-101, the acid zeolites H-ZSM-5, H-MOR, H-BETA and H-USY, and the solid superacids sulphated zirconia and niobium acid are selected. Comparative esterification experiments have been carried out using the homogeneous catalysts sulphuric acid, p toluenesulphuric acid and a heteropolyacid (HPA). The weight-based activity of the heterogeneous catalysts tested is maximum for Smopex 101. The following table gives the activity of different catalysts in the esterification reaction between acetic acid and butanol at 75^(@)C . Here: k_(obs) : observed reaction rate constant ( m^(3) mol^(-1)s^(-1) ) kc catalysed reaction rate constant ( m^(3)mol^(-1) g_(cat)^(-1)s^(-1) ) Please note: k c = k obs/ amount (in g) (source: PETERS, T., BENES, N., HOLMEN, A., & KEURENTJES, J. (2006). Comparison of commercial solid acid catalysts for the esterification of acetic acid with butanol. Applied Catalysis A: General, 297(2), 182-188. doi:10.1016/j.apcata.2005.09.00) The catalytic activity of homogeneous catalysts is high. The weight based activity of HPA is less than which of the following heterogenous catalysts?

Read the passage given below and answer the question: Industrially widely applied esterification reactions are commonly catalysed using mineral liquid acids, such as sulphuric acid and p-toluenesulphonic acid. The catalytic activity of homogeneous catalysts is high. They suffer, however, from several drawbacks, such as their corrosive nature, the existence of side reactions, and the fact that the catalyst cannot be easily separated from the reaction mixture. The use of solid acid catalysts offers an alternative and has received a lot of attention in the past years. Solid acid catalysts are not corrosive and, coated onto a support, they can be easily reused. Examples of solid acid catalysts used in esterification reactions include ion-exchange resins, zeolites and superacids like sulphated zirconia and niobium acid. Ion-exchange resins are the most common heterogeneous catalysts used and have proven to be effective in liquid phase esterification and etherification reactions. Because of their selective adsorption of reactants and swelling nature, these resins not only catalyse the esterification reaction but also affect the equilibrium conversion. Shortcomings include insufficient thermal resistance, which limits the reaction temperature to 120^(@)C , preventing widespread use in industry. Zeolites, like Y, X, BEA, ZSM-5 and MCM 41 offer an interesting alternative and have proven to be efficient catalysts for esterification reactions. Zeolites have found wide application in oil refining, petrochemistry and in the production of fine chemicals. Their success is based on the possibility to prepare zeolites with strong Brønsted acidity that can be controlled within a certain range, combined with a good resistance to high reaction temperatures. In this study, the activity of various commercial available solid acid catalysts is assessed with respect to the esterification of acetic acid with butanol. The ion-exchange resins Amberlyst 15 and Smopex-101, the acid zeolites H-ZSM-5, H-MOR, H-BETA and H-USY, and the solid superacids sulphated zirconia and niobium acid are selected. Comparative esterification experiments have been carried out using the homogeneous catalysts sulphuric acid, p toluenesulphuric acid and a heteropolyacid (HPA). The weight-based activity of the heterogeneous catalysts tested is maximum for Smopex 101. The following table gives the activity of different catalysts in the esterification reaction between acetic acid and butanol at 75^(@)C . Here: k_(obs) : observed reaction rate constant ( m^(3) mol^(-1)s^(-1) ) kc catalysed reaction rate constant ( m^(3)mol^(-1) g_("cat")^(-1)s^(-1) ) Please note: k c = k obs/ amount (in g) (source: PETERS, T., BENES, N., HOLMEN, A., & KEURENTJES, J. (2006). Comparison of commercial solid acid catalysts for the esterification of acetic acid with butanol. Applied Catalysis A: General, 297(2), 182-188. doi:10.1016/j.apcata.2005.09.00) Unit for observed rate constant for esterification reaction is m³ mol^-1s^-1 , so the reaction is:

Read the passage given below and answer the question: Industrially widely applied esterification reactions are commonly catalysed using mineral liquid acids, such as sulphuric acid and p-toluenesulphonic acid. The catalytic activity of homogeneous catalysts is high. They suffer, however, from several drawbacks, such as their corrosive nature, the existence of side reactions, and the fact that the catalyst cannot be easily separated from the reaction mixture. The use of solid acid catalysts offers an alternative and has received a lot of attention in the past years. Solid acid catalysts are not corrosive and, coated onto a support, they can be easily reused. Examples of solid acid catalysts used in esterification reactions include ion-exchange resins, zeolites and superacids like sulphated zirconia and niobium acid. Ion-exchange resins are the most common heterogeneous catalysts used and have proven to be effective in liquid phase esterification and etherification reactions. Because of their selective adsorption of reactants and swelling nature, these resins not only catalyse the esterification reaction but also affect the equilibrium conversion. Shortcomings include insufficient thermal resistance, which limits the reaction temperature to 120^(@)C , preventing widespread use in industry. Zeolites, like Y, X, BEA, ZSM-5 and MCM 41 offer an interesting alternative and have proven to be efficient catalysts for esterification reactions. Zeolites have found wide application in oil refining, petrochemistry and in the production of fine chemicals. Their success is based on the possibility to prepare zeolites with strong Brønsted acidity that can be controlled within a certain range, combined with a good resistance to high reaction temperatures. In this study, the activity of various commercial available solid acid catalysts is assessed with respect to the esterification of acetic acid with butanol. The ion-exchange resins Amberlyst 15 and Smopex-101, the acid zeolites H-ZSM-5, H-MOR, H-BETA and H-USY, and the solid superacids sulphated zirconia and niobium acid are selected. Comparative esterification experiments have been carried out using the homogeneous catalysts sulphuric acid, p toluenesulphuric acid and a heteropolyacid (HPA). The weight-based activity of the heterogeneous catalysts tested is maximum for Smopex 101. The following table gives the activity of different catalysts in the esterification reaction between acetic acid and butanol at 75^(@)C . Here: k_(obs) : observed reaction rate constant ( m^(3) mol^(-1)s^(-1) ) kc catalysed reaction rate constant ( m^(3)mol^(-1) g_(cat)^(-1)s^(-1) ) Please note: k c = k obs/ amount (in g) (source: PETERS, T., BENES, N., HOLMEN, A., & KEURENTJES, J. (2006). Comparison of commercial solid acid catalysts for the esterification of acetic acid with butanol. Applied Catalysis A: General, 297(2), 182-188. doi:10.1016/j.apcata.2005.09.00) The weight-based activity of the heterogeneous catalysts tested decreases in the following order:

Read the passage given below and answer the question: Industrially widely applied esterification reactions are commonly catalysed using mineral liquid acids, such as sulphuric acid and p-toluenesulphonic acid. The catalytic activity of homogeneous catalysts is high. They suffer, however, from several drawbacks, such as their corrosive nature, the existence of side reactions, and the fact that the catalyst cannot be easily separated from the reaction mixture. The use of solid acid catalysts offers an alternative and has received a lot of attention in the past years. Solid acid catalysts are not corrosive and, coated onto a support, they can be easily reused. Examples of solid acid catalysts used in esterification reactions include ion-exchange resins, zeolites and superacids like sulphated zirconia and niobium acid. Ion-exchange resins are the most common heterogeneous catalysts used and have proven to be effective in liquid phase esterification and etherification reactions. Because of their selective adsorption of reactants and swelling nature, these resins not only catalyse the esterification reaction but also affect the equilibrium conversion. Shortcomings include insufficient thermal resistance, which limits the reaction temperature to 120^(@)C , preventing widespread use in industry. Zeolites, like Y, X, BEA, ZSM-5 and MCM 41 offer an interesting alternative and have proven to be efficient catalysts for esterification reactions. Zeolites have found wide application in oil refining, petrochemistry and in the production of fine chemicals. Their success is based on the possibility to prepare zeolites with strong Brønsted acidity that can be controlled within a certain range, combined with a good resistance to high reaction temperatures. In this study, the activity of various commercial available solid acid catalysts is assessed with respect to the esterification of acetic acid with butanol. The ion-exchange resins Amberlyst 15 and Smopex-101, the acid zeolites H-ZSM-5, H-MOR, H-BETA and H-USY, and the solid superacids sulphated zirconia and niobium acid are selected. Comparative esterification experiments have been carried out using the homogeneous catalysts sulphuric acid, p toluenesulphuric acid and a heteropolyacid (HPA). The weight-based activity of the heterogeneous catalysts tested is maximum for Smopex 101. The following table gives the activity of different catalysts in the esterification reaction between acetic acid and butanol at 75^(@)C . Here: k_(obs) : observed reaction rate constant ( m^(3) mol^(-1)s^(-1) ) kc catalysed reaction rate constant ( m^(3)mol^(-1) g_(cat)^(-1)s^(-1) ) Please note: k c = k obs/ amount (in g) (source: PETERS, T., BENES, N., HOLMEN, A., & KEURENTJES, J. (2006). Comparison of commercial solid acid catalysts for the esterification of acetic acid with butanol. Applied Catalysis A: General, 297(2), 182-188. doi:10.1016/j.apcata.2005.09.00) Which of the following are heterogeneous catalysts for esterifctaion reaction:

A disc of radius r = 0.1 m is rolled from a point A on a track as shown in the figure. The part AB of the track is a semi-circle of radius R in a vertical plane. The disc rolls without sliding and leaves contact with the track at its highest point B. Flying through the air it strikes the ground at point C. The velocity of the center of mass of the disc makes an angle of 30^(@) below the horizontal at the time of striking the ground. At the same instant, velocity of the topmost point P of the disc is found to be 6 m//s (Take g = 10 m//s^(2) ). (a) Find the value of R. (b) Find the velocity of the center of mass of the disc when it strikes the ground. (c) Find distance AC.

A thermodynamic process is shown in the following figure. In the process AB, 600 J of heat is added to the system and in BC, 200 J of heat is added to the system. The change in internal energy of the system in the process AC would be: P_(A) = 3 xx 10^(4) Pa, V_(A) = 2xx 10^(-3) m^(3) P_(B) = 8 xx 10^(4) Pa, V_(C) = 5 xx 10^(-3) m^(3)